Comorbidities of Community-Dwelling Older Adults with Urinary Incontinence: A Scoping Review

Abstract

Background:

Identifying comorbidities is a critical first step to building clinical phenotypes to improve assessment, management, and outcomes.

Objectives:

1) Identify relevant comorbidities of community-dwelling older adults with urinary incontinence, 2) provide insights about relationships between conditions.

Methods:

PubMed, Cumulative Index of Nursing and Allied Health Literature, and Embase were searched. Eligible studies had quantitative designs that analyzed urinary incontinence as the exposure or outcome variable. Critical appraisal was performed using the Joanna Briggs Institute Critical Appraisal Checklists.

Results:

Ten studies were included. Most studies had methodological weaknesses in the measurement of conditions. Comorbidities affecting the neurologic, cardiovascular, psychologic, respiratory, endocrine, genitourinary, and musculoskeletal systems were found to be associated with urinary incontinence.

Conclusion:

Existing literature suggests that comorbidities and urinary incontinence are interrelated. Further research is needed to examine symptoms, shared mechanisms, and directionality of relationships to generate clinical phenotypes, evidence-based holistic care guidelines, and improve outcomes.

Introduction

Urinary incontinence (UI) (i.e., the involuntary leakage of urine¹) affects over 40% of community-dwelling older adults aged 60 years and older^2,3; yet often goes untreated due to a lack of care seeking and screening.^4–6 Most older adults do not report UI to clinicians^7–9 due to embarrassment^10,11 and the belief that UI is part of normal aging.^4,6 Clinician-initiated assessments of UI are preferred,¹⁰ however these assessments do not consistently take place.^10,12 UI can be associated with several negative outcomes, including urinary tract infections,¹³ skin breakdown,¹⁴ cognitive decline,¹⁵ falls,¹⁶ and fractures,¹⁷ all of which can be precursors to hospitalization and mortality.¹⁸ Despite these serious risks, UI may be perceived by clinicians as less important than other comorbid conditions.¹⁹ Most older adults with UI have chronic comorbid conditions²⁰ that can initiate or exacerbate UI. For this reason, older adults with UI likely have symptoms affecting several physiological systems. This complicates the assessment of these patients as they present with co-occurring symptoms, which are more challenging to identify and manage compared to individually occurring symptoms.^21,22 Given the interconnectedness of physiological systems, biological, and psychological factors that contribute to UI,^5,19 a clear evaluation process that accounts for multiple co-occurring symptoms in a systematic way is warranted.²³

Despite this need, clinical assessment of UI is often limited to the urological system.²⁴ This is noted in clinical practice guidelines, which typically focus on individual conditions,²⁵ which promotes fragmented specialty-specific health care.²⁶ This leads to missed opportunities to comprehensively assess and manage older adults with UI and other comorbid conditions.^5,19 For example, current evidence-based recommendations for assessing and managing UI focus on evaluating voiding patterns, identifying the type of UI based on urinary symptoms, and reviewing medications that may affect the lower urinary tract.²⁴ Additionally, clinical assessment of patients with heart failure typically focuses on volume status and perfusion by evaluating for orthopnea, jugular venous distention, and edema.²⁷ However, these recommendations only target symptoms related to one condition and do not reflect the holistic approach needed to care for patients with UI⁵; such an approach recognizes the person as a whole, the context of the environment, and the mind-body connection.²⁸ Evidence-based holistic care guidelines that account for several conditions and co-occurring symptoms can improve assessing and managing patients with multiple comorbidities. This holistic approach can improve UI and other comorbid conditions by facilitating earlier identification, prevention, and management strategies.¹⁹ Well-defined clinical phenotypes are essential to inform evidence-based holistic care. Clinical phenotypes in medical and nursing contexts are defined as groups of observable traits that deviate from normal physiology or behavior.²⁹ These traits can be operationalized as comorbidities or symptoms in research. Clinical phenotypes remain an enigma for community-dwelling older adults with UI, leading to delayed diagnosis, treatment, and worse outcomes. Clinical phenotypes can allow clinicians to systematically assess these complex patients, recognize co-occurring symptoms across physiological systems, and stratify treatments to provide holistic care. Identifying comorbidities of community-dwelling older adults with UI is a critical first step to building clinical phenotypes by guiding future symptom-based research to improve assessment, management, and outcomes.

Community-dwelling older adults are unique as the experience and impact of UI differ from that of older adults in other settings, such as nursing homes and hospitals. UI in nursing homes is often related to dementia and mobility impairment,³⁰ resulting in more severe symptoms and increased caregiver dependence compared to UI in the community.³¹ Managing hospitalized older adults with UI focuses on containment strategies rather than treating the condition and promoting continence.³² Community-dwelling older adults with UI are often managing chronic conditions and living with the impacts of UI across personal (e.g., quality of life), interpersonal (e.g., intimate, familial, social, and workplace relationships), organizational (e.g., missed work, reduced productivity), community (e.g., stigma, social isolation), societal (e.g., increased health care utilization and costs), and ecosystem (e.g., increased water use from toilet flushing, increased waste from pad use) levels.^5,19 Further, the cumulative aspect of comorbidities involves managing fluctuating symptoms in the community setting throughout the life course.³³ A life course perspective supports that UI and other health conditions may develop at any point and the aggregate impact can increase over time¹⁹; therefore, impacts are likely more significant with age. Community-dwelling older adults with UI and multiple comorbid conditions typically visit an increasing number of specialty-specific clinicians over time. This leads to fragmented care and the formation of silos, in which the broader context of the entire clinical phenotype may be missed.³⁴ In the absence of well-defined clinical phenotypes and evidence-based holistic care guidelines, it is challenging for clinicians to navigate assessment and management strategies for older adults throughout the life course. Given differences in health, functional status, and needs between institutionalized and community populations,³⁵ a study specific to community-dwelling older adults with UI is warranted.

The lack of understanding about comorbidities associated with UI among older adults, directionality of these relationships, and shared mechanisms inhibits the development of clinical phenotypes and leads to fragmented assessment and management strategies.¹⁹ Existing evidence suggests the association of comorbidities outside the urinary tract and UI^36–39; however, these studies were not specific to older adults with UI, leaving a gap in the literature for this study to address. The underreporting and undertreating of UI and its association with negative outcomes underscore the need for improved assessment and management strategies. Moreover, alarming evidence exists that many ill older adults consider UI a health state worse than death,⁴⁰ which further underpins this need.

Knowledge of comorbidities of community-dwelling older adults with UI can improve clinicians’ ability to employ comprehensive assessments and timely interventions to reduce the risk of negative outcomes. Specifically, this knowledge can form a basis for developing clinical phenotypes and evidence-based holistic care guidelines that standardize assessments of multiple comorbidities and co-occurring symptoms. Further, this can increase clinicians’ awareness of the need to screen for UI when patients present with certain comorbidities. This can lead to UI being more readily identified and treated before negative outcomes develop. Given the rising number of older adults with UI due to the growth of the aging population,⁴¹ this study is well-timed to broadly characterize community-dwelling older adults with UI and provide a foundation for developing clinical phenotypes and evidence-based holistic care guidelines in future research. Specifically, the objectives of this study are to: 1) review the literature to identify relevant comorbidities among community-dwelling older adults with UI to inform future symptom-based research, and 2) provide insights about relationships between comorbidities and UI to improve assessment and management strategies.

Methods

A scoping review was chosen instead of a systematic review as the purpose was to address a broad research question that aimed to identify significant comorbidities among community-dwelling older adults with UI and map existing evidence⁴² by categorizing comorbidities by affected physiological system. Additionally, this review will enhance foundational knowledge specific to older adults to provide a basis for future symptom-based research involving this population.⁴² This scoping review was reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) guidelines.⁴³ The review involved the following phases: study retrieval, study selection, critical appraisal, data extraction, and data synthesis. Study selection, critical appraisal, and data extraction were performed using Covidence (www.covidence.org), a web-based tool designed to facilitate these processes.

A protocol for study eligibility was developed a priori and listed in the Open Science Framework database (https://osf.io/a2xmw/). The protocol is reported in accordance with the PRISMA-ScR statement.⁴³

Eligibility Criteria

The search included studies from database inception through March 2023. There were no restrictions by publication date. Consistent with the World Health Organization’s definition of “aged,” older adults were defined as individuals aged 60 years and older.⁴⁴ Adults 60 years of age and older were selected as the population of focus because older adults have an especially high risk for negative outcomes secondary to UI and many older adults with UI have multiple chronic conditions.⁴⁵ UI was defined as the involuntary leakage of urine.¹ UI subtypes include stress (i.e., involuntary leakage of urine with physical exertion or effort, such as coughing, sneezing, or sporting activities), urgency (i.e., involuntary leakage of urine preceded by the sudden desire to pass urine which is difficult to defer), and mixed (i.e., involuntary leakage of urine associated with physical exertion or effort and urgency).¹ Comorbidity was defined in the domain of clinical care as the co-occurrence of distinct diseases in any physiologic system.⁴⁶ Inclusion criteria were: 1) quantitative study designs evaluating associations between comorbidities and UI among community-dwelling older adults (aged 60 years and older) that analyzed UI as either the exposure or the outcome variable, 2) articles written in English or translated to the English language, and 3) full-text article is available. Studies were excluded if they: 1) took place in inpatient, nursing home, or post-acute care settings (i.e., long-term care, home healthcare, skilled nursing facility, or rehabilitation settings), 2) evaluated older adults with UI secondary to urinary tract infections, sexually transmitted infections, medication side effects, surgery, primary neurogenic lower urinary tract dysfunction (i.e., due to congenital neurological disorders and spinal cord injury), or prostate cancer, 3) evaluated older adults with dual incontinence (i.e., UI and fecal incontinence), 4) focused on treatment and management of UI (e.g., medication or surgical interventions and outcomes), and 5) were review articles, qualitative studies, study protocols, dissertation studies, editorials, psychometric studies, case reports, and unpublished articles.

These criteria were established to only include studies specific to community-dwelling adults with UI without influence from acute conditions, medications, or surgery. Older adults with primary neurogenic lower urinary tract dysfunction were excluded because lower urinary tract dysfunction due to congenital neurological disorders or spinal cord injuries should be studied separately.⁴⁷ Older adults with prostate cancer were excluded because of medical complexity and increased frequency of UI secondary to management strategies (e.g., surgery).⁴⁸ Additionally, older adults with dual incontinence were excluded because this is a severe type of pelvic floor dysfunction that affects individuals differently than UI or fecal incontinence in isolation.^49,50 Further, evidence exists that comorbidities are more common among individuals with dual incontinence than UI alone,⁵⁰ which indicates that including this population in this study could overestimate comorbidities among older adults with UI.

Information Sources

Three databases were searched (PubMed, Cumulative Index of Nursing and Allied Health Literature (CINAHL), and Embase) in March 2023 to identify potentially relevant studies related to comorbidities among community-dwelling older adults with UI. Reference lists of included studies were manually searched for additional relevant studies.

Search Strategy

The author (DS) developed the search strategy which was revised in consultation with the co-authors (SH, MT) and the Columbia University School of Nursing Health Sciences Library Informationist (JU). Search terms that described the concepts of older adults, comorbidities, and UI included a combination of Medical Subject Heading (MeSH) vocabulary and keywords (Table 1). The terms used to operationalize these concepts in the literature were selected to capture relevant studies focusing on comorbidities among community-dwelling older adults with UI. Full search strategies applied in PubMed, CINAHL, and Embase are presented in Table 2.

Table 1.

Concepts and Related Terms

Concepts	Related terms for search
Older adults	Aged, older adult, elderly, geriatric
Comorbidities	Comorbidities, comorbidity, comorbid, chronic condition, chronic disease
Urinary incontinence	Urinary incontinence, urgency urinary incontinence, urge urinary incontinence, urge incontinence, stress urinary incontinence, stress incontinence, mixed urinary incontinence, mixed incontinence

Table 2.

Search Strategies Used to Retrieve Articles

Database	Search strategy	Publications retrieved
PubMed	(“Aged”[Mesh] OR “older adult”[tiab] OR “elderly”[tiab] OR “geriatric”[tiab]) AND (“Comorbidity”[Mesh] OR “comorbid*”[tiab] OR “chronic condition”[tiab] OR “chronic disease”[tiab]) AND (“Urinary Incontinence”[Mesh] OR “urinary incontinence”[tiab] OR “urgency urinary incontinence”[tiab] OR “urge urinary incontinence”[tiab] OR “urge incontinence”[tiab] OR “stress urinary incontinence”[tiab] OR “stress incontinence”[tiab] OR “mixed urinary incontinence”[tiab] OR “mixed incontinence”[tiab])	870 3/1/2023
CINAHL	((MH “Aged”) OR TI (“older adult” OR “elderly” OR “geriatric”) OR AB (“older adult” OR “elderly” OR “geriatric”)) AND ((MH “Comorbidity”) OR TI (“comorbid*” OR “chronic condition” OR “chronic disease”) OR AB (“comorbid*” OR “chronic condition” OR “chronic disease”)) AND ((MH “Urinary Incontinence”) OR TI (“urinary incontinence” OR “urgency urinary incontinence” OR “urge urinary incontinence” OR “urge incontinence” OR “stress urinary incontinence” OR “stress incontinence” OR “mixed urinary incontinence” OR “mixed incontinence”) OR AB (“urinary incontinence” OR “urgency urinary incontinence” OR “urge urinary incontinence” OR “urge incontinence” OR “stress urinary incontinence” OR “stress incontinence” OR “mixed urinary incontinence” OR “mixed incontinence”))	343 3/1/2023
Embase	(‘aged’/exp OR ‘older adult’:ti,ab OR ‘elderly’:ti,ab OR ‘geriatric’:ti,ab) AND (‘comorbidity’/exp OR ‘comorbid*’:ti,ab OR ‘chronic condition’:ti,ab OR ‘chronic disease’:ti,ab) AND (‘urinary incontinence’/exp OR ‘urinary incontinence’:ti,ab OR ‘urgency urinary incontinence’:ti,ab OR ‘urge urinary incontinence’:ti,ab OR ‘urge incontinence’:ti,ab OR ‘stress urinary incontinence’:ti,ab OR ‘stress incontinence’:ti,ab OR ‘mixed urinary incontinence’:ti,ab OR ‘mixed incontinence’:ti,ab)	1634 3/1/2023

Selection of Sources of Evidence

All potentially relevant studies were imported to EndNote X9 software and deduplicated using the Bramer method.⁵¹ To determine eligibility for inclusion, two reviewers (DS, SH) independently screened all studies by title and abstract using Covidence (www.covidence.org). The same two reviewers independently screened the full-text studies and documented reasons for exclusion. A third reviewer was consulted to resolve discrepancies (MT).

Data Charting Process

The author (DS) created the data extraction template, which was revised in consultation with the co-authors (SH, MT). The rationale and objectives of the current scoping review guided variable selection. The template was tested and continuously revised to include variables pertinent to the research question.

Data Items

The variables of interest for data extraction included authors, year of publication, country, study design, purpose, sample, type of UI studied, data source, significant comorbidities of community-dwelling older adults with UI, measurement of UI and significant comorbidities, and study outcomes. Data was summarized in tables to identify patterns and facilitate data synthesis.

Critical Appraisal of Individual Sources of Evidence

Methodological quality and risk of bias in design, implementation, and data analysis of each included study were assessed based on the Joanna Briggs Institute (JBI) Critical Appraisal Checklist for Analytical Cross-Sectional Studies (for the 8 cross-sectional studies), JBI Critical Appraisal Checklist for Cohort Studies (for the one cohort study) and JBI Critical Appraisal Checklist for Case-Control studies (for the one case-control study).⁵² The Critical Appraisal Checklist for Analytical Cross-Sectional Studies contains eight questions, the Critical Appraisal Checklist for Cohort Studies contains 11 questions, and the Critical Appraisal Checklist for Case-Control Studies contains 10 questions. Response options for each question are: “yes,” “no,” “unclear,” or “not applicable.” These tools were used to assess methodological quality and risk of bias in sampling, measurement, and data analysis. No studies were excluded based on the results of the critical appraisal.

Synthesis of Results

The findings about significant comorbidities of community-dwelling older adults with UI were summarized and grouped based on the affected physiological system. Physiological system was extended to include “psychologic” to capture the impact of UI beyond the biological system. This summary also included information about samples, methods, and measurements used in each study.

Results

Selection of Sources of Evidence

A summary of the study selection process is provided in the PRISMA flow diagram (Figure 1). The initial literature search yielded 2,847 potentially eligible studies. After deduplication, 2,085 studies were included for the title and abstract screening. Thirty-eight studies were included for full-text review. Twenty-nine studies were excluded. Reasons for exclusion are provided in Figure 1. Nine studies met eligibility criteria and were included for critical appraisal and data extraction. Reference lists of the nine included studies were manually searched, and one study met inclusion criteria, for a total of 10 studies to be included in this scoping review.

Figure 1.

PRISMA Flow Diagram of Article Selection Process

Characteristics of Sources of Evidence

Ten studies met the inclusion criteria^53–62 and represent data from 28,330 community-dwelling older adults with UI across several disease types (i.e., stroke, Parkinsonism, cerebrovascular disease, heart disease, hypertension, congestive heart failure, diabetes, chronic obstructive pulmonary disease, sarcopenia, arthritis, benign prostatic hyperplasia, depression, and anxiety). Characteristics of the ten included studies are presented in Table 3. The studies were published between 1996 and 2021 and were conducted across four countries (i.e., the United States^{53–55,57,59,61}, Brazil,⁵⁶ Turkey,⁵⁸ and Korea^60,62). Four studies (40%) included women and men,^55–57,61 four studies (40%) included women only,^53,54,58,62 and two studies (20%) included men only.^59,60 Of the studies that included women and men, samples ranged from roughly 55 to 90% women. Four studies (40%) solely focused on Mexican American men,⁵⁹ Latino adults,⁶¹ Korean women,⁶² and Korean men.⁶⁰ Of the remaining studies (n = 6), all but two^55,58 reported race and ethnicity data. Of the studies that reported these data, most samples mainly included (i.e., greater than 60%) White participants. Regarding type of UI studied, four studies (40%) specified UI subtype and included older adults with stress,^56,58,60 urgency,^55,58–60 and mixed UI.^56,58,60

Table 3.

Characteristics of Sources of Evidence

Author, year	Country	Study design	Study purpose	Study sample	Type of UI studied	Data source	Measurement of UI	Measurement of significant comorbidities
Bresee et al., 2014	United States	Cross-sectional	To determine UI prevalence and associated factors (sociodemographic, overall health status, medical conditions) to quantify the burden of UI among older community-dwelling women.	5374 community-dwelling women aged 65 and older in California; 69.29% non-Hispanic White, 11.44% Asian, 10.61% Hispanic, 5.44% African American, 3.21% Other	Not specified	CHIS 2003	CHIS question: “In the past 30 days, have you been incontinent, that is unable to hold or control your urine more than once?”	Self- report of medical comorbidities
Brown et al., 1996	United States	Cross-sectional	To examine the prevalence of UI and associated factors among older women.	7949 community-dwelling women aged 69–101 years; excluded Black women due to low incidence of osteoporotic fractures; race and ethnicity data otherwise not specified	Not specified	The Study of Osteoporotic Fractures	Questionnaire: “During the last 12 months have you ever leaked urine or lost control of your urine?”	Self-report questionnaire about comorbidities
Buchman et al., 2017	United States	Prospective cohort	To determine if UI is associated with incident parkinsonism in community-dwelling older adults.	2617 women and men aged 65 and older without dementia who were Catholic nuns, priests, lay brothers, and residents of retirement communities and subsidized housing in Chicago; 73.5% women, 26.5% men; did not specify race and ethnicity data	Not specified	The Religious Orders Study and the Rush Memory and Aging project	Self-report ordinal scale for frequency of UI episodes	26-item Unified Parkinson’s Disease Rating Scale
Burti et al., 2012	Brazil	Cross-sectional	To determine the prevalence of UI and associated factors among low-income older adults.	388 community-dwelling women and men aged 65 years and older with no mobility or cognitive deficits living in low-income areas of Sao Paulo, Brazil; 63% women, 37% men; 62% White, 34% Black, 4% Asian	Stress UI, urge UI, and mixed UI (stress and urge UI)	Collaborative program developed by the 10/66 Dementia Research Group	Structured interview question: “Do you leak urine or have you lost control of your urine during the last 12 months?”	Blood pressure and diabetes measurements taken in the hospital
Divani et al., 2011	United States	Case-control	To determine the risk of developing post-stroke health problems, including UI.	Cases: 631 women and men age 68 years and older who had a first ever stroke from 1998–2006; 53% female, 75% Non-Hispanic White, 16% Black/Other race, 8% Hispanic Controls: 631 older adults who did not have a stroke 53% female, 79% Non-Hispanic White, 15% Black/Other race, 6% Hispanic	Not specified	Health and Retirement Study database	Self-report (face-to face or telephone interview) of the involuntary loss of urine within the past 12 months	Self-report (face-to face or telephone interview); asked participants if a physician has diagnosed them with medical comorbidities
Erdogan et al. 2019	Turkey	Cross-sectional	To examine the relationship between stress and/or urge urinary incontinence and sarcopenia among older women.	802 women aged 60 years and older who were seen at a geriatric outpatient university hospital clinic from 11/2012 – 11/2016; did not specify race and ethnicity data	Stress UI, urge UI, mixed UI	Face-to-face interviews;	Interviews; self-report of UI defined as “the complaint of any involuntary leakage of urine in the past 12 months”	Geriatric physiotherapist performed all measurements related to sarcopenia; standardized stadiometer (to measure height and weight), bioimpedance analysis with body analysis monitor (to measure body composition)
Gerst et al., 2011	United States	Cross-sectional	To investigate the prevalence, risk factors, and consequences of urge urinary incontinence among older Mexican-American men.	700 Mexican-American men aged 75 years and older from five Southwestern states (Texas, New Mexico, California, Arizona, Colorado)	Urge UI	The fifth wave of the Hispanic Established Population for the Epidemiologic Study of the Elderly	Self-report question: “How often do you have difficulty holding your urine until you can get to a toilet?” with 5-point Likert-type response options (never, hardly ever, some of the time, most of the time, all of the time)	Self-report question asking participants if a healthcare provider had ever told them they had prostate problems.
Park & Son Hong, 2016	Korea	Cross-sectional	To identify the prevalence of UI and examine the association between UI and benign prostatic hyperplasia and functional ability (i.e., instrumental activities of daily living) in community-dwelling older men in Korea.	6,185 community-dwelling Korean men age 60 years and older	Stress UI, urge UI, mixed UI	Actual Living Condition of the Elderly and Welfare Need Survey conducted by the Korean Ministry of Health and Welfare	Self report; asked participants “Do you have UI?”	Self report; asked participants “Do you have BPH which was diagnosed by doctor?”
Smith et al., 2010	United States	Cross-sectional	To evaluate the prevalence and correlates of UI among older community dwelling Latino adults.	572 Latino women and men 60 years and older from 27 community based senior centers; 77.1% women, 22.9% men	Not specified	Caminemos: a clinical trial of a behavioral intervention to increase walking levels	International Consultation on Incontinence Questionnaire	In-person survey; Charlson Comorbidity Index to quantify the number of comorbid conditions
Sohn et al., 2018	Korea	Cross-sectional	To examine the characteristics of patients with UI and evaluate the association of UI with other geriatric health problems.	2418 community-dwelling Korean women aged 65 years and older	Not specified	Korean Longitudinal Study of Aging	Self-report yes/no question: “Have you experienced urine leakage in the past 12 months?”	Self-report; asked participants if they were diagnosed with specific diseases by a doctor

Note. UI, urinary incontinence; CHIS, California Health Interview Survey

Critical Appraisal Within Sources of Evidence

Details of the critical appraisal of the studies according to the JBI Critical Appraisal Checklists are provided in Tables 4, 5, and 6. Nine studies^{53,54,56–62} examined comorbidities as the exposure and UI as the outcome. The only included prospective cohort study⁵⁵ examined UI as the exposure and comorbidities (i.e., Parkinsonism) as the outcome. Most studies (n=6; 60%)^{53–55,57,59,61} received “yes” responses in most critical appraisal checklist domains, indicating that the criteria for methodological quality in that domain was met. The remaining studies (n=4; 40%) received “yes” responses in half ^56,58,60 and less than half ⁶² of critical appraisal checklist domains.

Table 4.

Critical Appraisal of Cross-Sectional Studies

	Cross-sectional studies (n = 8)
Joanna Briggs Institute Checklist Questions	Bresee et al., 2014	Brown et al., 1996	Burti et al., 2012	Erdogan et al. 2019	Gerst et al., 2011	Park & Son Hong, 2016	Smith et al., 2013	Sohn et al., 2018
Were the criteria for inclusion in the sample clearly defined?	Yes Women aged 65 years and older living in California who completed the CHIS in 2003.	Yes Women aged 69–101 years in the Study of Osteoporotic Fractures. Women with bilateral hip replacement and those unable to walk were excluded.	Yes Adults aged 65 years and older with no mobility or cognitive deficits living without institutional support.	Yes Women aged 60 years and older without cognitive deficits who were seen at a geriatric outpatient clinic from 11/2012–11/2016. Excluded women with functional or overflow incontinence	Yes Mexican American men aged 75 years and older from Wave five of the Hispanic Established Population for the Epidemiologic Study of the Elderly. Excluded men with a urinary catheter.	Yes 6,185 men aged 60 years and older who participated in the 2008 Actual Living Condition of the Elderly and Welfare Need Survey	Yes Adults aged 60 years and older who self-identify as Latino, speak English or Spanish, passed the six item cognitive screening with a score of 4/6 or higher, and exercise less than one hour/week.	No Provided vague information about inclusion criteria: women who responded yes to “have you experienced urine leakage in the past 12 months?”
Were the study subjects and the setting described in detail?	Yes Table 1 describes study subjects. Setting: California communities (stratified into 41 counties) from 8/2003 – 2/2004	Yes Table 1 describes study subjects. Setting: outpatient clinics in Maryland, Minnesota, Pennsylvania, and Oregon	Yes Table 1 describes study subjects. Setting: low-income areas of San Paulo, Brazil	No Table 1 describes sample age and prevalence of comorbidities but does not report sample race and ethnicity. Setting: geriatric outpatient clinic from 11/2012 – 11/2016	Yes Table 1 describes study subjects. Setting: communities in five south western states (Texas, New Mexico, California, Arizona, Colorado)	No Table 1 describes the general characteristics of participants including age, education, body mass index, comorbidities, number of limited instrumental activities of daily living, and walking speed in seconds. Setting was not described in detail	Yes Table 1 describes study subjects. Setting: 27 community based senior centers in the greater Los Angeles area	No Although Table 1 describes study subjects, setting is not described in detail
Was the exposure measured in a valid and reliable way?	No Exposure: comorbidities (heart disease, any cancer diagnosis, cervical cancer, stroke) Professional interviewers measured comorbidities by self-report using a computer assisted telephone interview system. No detail about qualifications or training of the professional interviewers. Data was collected and reported by one observer.	No Exposure: comorbidities (diabetes, stroke, COPD, asthma, CHF, Parkinson’s disease) Participants completed a questionnaire about presence of comorbidities. No information about questionnaire items or validity and reliability of the questionnaire	Unclear Exposure: comorbidities (HTN, diabetes, osteopenia, osteoporosis) Blood pressure, diabetes, and bone density measures were taken at the hospital. No detail provided about that qualifications or training of who performed these measures or what these measures entailed (e.g., how blood pressure was taken, laboratory tests for fasting blood sugar or non-fasting blood sugar, hemoglobin A1C, fingerstick blood sugar, bone scan).	Yes Exposure: comorbidities (sarcopenia) Measures for the diagnosis of sarcopenia were taken by the same trained geriatric physiotherapist using standardized instruments and validated protocols.	No Exposure: comorbidities (MI, stroke, HTN, cancer, arthritis, diabetes, hip fracture, prostate conditions) Measured by self-report by asking participants if a health care provider ever told them they had any of the specified conditions.	No Exposure: comorbidities (BPH) Measured by self-report by asking “Do you have BPH which was diagnosed by doctor?”	No Exposure: comorbidities (HTN, MI, CHF, stroke, diabetes, arthritis, hip fracture, asthma, emphysema, COPD, chronic bronchitis, cirrhosis or liver disease, cancer (other than skin), Parkinson’s disease, Alzheimer’s disease, dementia, depression, anxiety) Participants completed an in-person survey about health conditions and a brief physical examination. Number of comorbidities was quantified with the Charlson Comorbidity Index. No information provided about survey questions or what the physical examination entailed.	No Exposure: comorbidities (HTN, diabetes, chronic lung disease, cerebrovascular disease, arthritis). Measured by self-report by asking participants whether they were diagnosed by a health care provider with any of the specified conditions.
Were objective, standard criteria used for measurement of the condition?	No UI was measured by asking participants a self-report yes/no question from the CHIS: “In the past 30 days have you been incontinent, that is, unable to hold or control your urine more than once?”	No UI was measured by a questionnaire that included the questions: “During the last 12 months have you ever leaked urine or lost control of your urine?,” “If yes, how often does this leakage of urine usually occur?”	No UI was measured in interviews, during which participants were asked, “Do you leak urine or have you lost control of your urine during the last 12 months?” Participants answering “yes” were characterized by subtype: stress UI if leakage happened during effort, cough, or laugh, urge UI if leakage was sudden and uncontrolled, and mixed UI if leakage was reported in both conditions.	No UI was measured in interviews, during which participants were asked if they had “any involuntary leakage of urine in the past 12 months.” If yes, UI subtype was determined by asking “When does your leakage usually occur?” with response options: with coughing, lifting, standing up, or exercise (stress UI), when you have the urge to urinate and cannot get to a toilet fast enough (urge UI)	No UI was measured by asking participants a self-report question: “How often do you have difficulty holding your urine until you can get to a toilet?” with 5-point Likert-type response options: never, hardly ever, some of the time, most of the time, or all of the time. Which the The authors assert this question has been used in literature to indicate UI, including among Mexican Americans; however the definition of UI is not consistent with standard criteria.	No UI was measured by self-report: “Do you have UI?”	No UI was measured using an item from the ICIQ: “How often do you leak urine?” with six response options: never, less than one time per week, two to three times per week, once per day, several times per day, or all the time. Participants who responded anything other than “never” were classified as having UI.	No UI was measured by self-report yes/no question: “Have you experienced urine leakage in the past 12 months?”
Were confounding factors identified?	Yes Age, gender, race, ethnicity, citizenship status, primary language, education, employment, income, health status, body mass index, fall in the past 12 months, HRT, smoking regular walking, medical visits.	Yes Age, menopausal years, number of live births, hysterectomy, body mass index, medications, coffee intake, smoking status, alcohol use, physical exercise, gait speed, muscle strength.	Yes Age, race, years of education, number of pregnancies, medications, body mass index.	Yes Age, fecal incontinence, constipation, height, weight, body mass index, functional status.	Yes Whether or not the participant saw a physician in the last year, English or Spanish language, marital status, education, age, activities of daily living limitations.	Yes Age, education, body mass index, hypertension, diabetes, stroke, depression, walking speed	Yes Age, gender, marital status, level of education, income, smoking status, cognitive function, acculturation	Yes BMI, education, marital status, smoking status, alcohol intake, social activity.
Were strategies to deal with confounding factors stated?	Yes Multi-variable logistic regression analysis; also considered interactions between age, race, and ethnicity.	Yes Multi-variable logistic regression analysis.	No Adjusted analysis was done with BMI and diabetes but no other adjusted analyses were done for other potentially confounding factors.	No Multi-variable logistic regression analysis only adjusted for weight, height, and BMI and did not adjust for other potential confounding factors.	Yes Multi-variable regression models.	Yes Hierarchical logistic regression models adjusting for confounders.	Yes Multi-variable logistic regression analyses (five models).	Unclear Unclear which covariates were used in adjusted multivariable logistic regression analyses.
Were the outcomes measured in a valid and reliable way?	No Outcome: UI UI was measured by self-report yes/no question. No information about the validity and reliability of the CHIS question.	No Outcome: UI UI was measured by self-report questionnaire No information about validity or reliability of the questionnaire	No Outcome: UI UI was measured during interviews conducted by a trained professional. No information provided about qualifications or training of the interviewers.	No Outcome: UI UI was measured by self-report interview questions. No information about validity or reliability of the questions was provided. No detail about who conducted the interviews, their qualifications or training.	No Outcome: UI UI was measured by asking a self-report question with 5-point Likert-type response options. No discussion of interview procedure, training of interviewer, or validity or reliability of the question.	No Outcome: UI UI was measured by self-report question: “Do you have UI?”	Yes Outcome: UI UI was measured using an item modified from the ICIQ, a tool that generates valid and reliable scores.	No Outcome: UI UI was measured with a self-report yes/no question. No information about validity or reliability of the question.
Was appropriate statistical analysis used?	Yes Used chi-square tests to test associations between UI (categorical variable – yes/no) and demographic and medical variables; used logistic regression to determine odds ratios.	Yes Chi-square tests to evaluate factors potentially associated with UI (categorical variables).	Yes Kruskal Wallis test was used when the variable did not meet the normality assumption. Used Fisher’s exact test when >20% of expected cell counts were less than 5, otherwise used chi-square tests.	Yes Used t tests for continuous variables, chi-square tests for categorical variables, Fisher’s exact tests when >20% of expected cell counts were less than 5.	Yes Used t tests for continuous variables and chi square tests for categorical variables.	Yes Hierarchical logistic regression analysis to determine odds ratios	Yes Used t tests for continuous variables, chi- square tests for categorical variables, and multivariable logistic regression models to estimate odds ratios.	Yes Used t tests for continuous variables, chi-square tests for categorical variables, Fisher’s exact test when >20% of expected cell counts were less than 5, and univariable and multivariable logistic regression.

Note. CHIS, California Health Interview Survey; UI, urinary incontinence; COPD, chronic obstructive pulmonary disease; CHF, congestive heart failure; MI, myocardial infarction; HTN, hypertension; ICIQ, International Consultation on Incontinence Questionnaire; HRT, hormone replacement therapy; BMI, body mass index

Table 5.

Critical Appraisal of Cohort Studies

Joanna Briggs Institute Checklist Questions	Buchman et al., 2017
Were the two groups similar and recruited from the same population?	Yes Recruited from the Religious Orders Study and the Rush Memory and Aging Project. Inclusion/exclusion criteria were explicitly stated. Groups (no UI, n = 1370 and UI, n = 1247) had similar demographics, disability, cognition, and chronic health conditions.
Were the exposures measured similarly to assign people to both exposed and unexposed groups?	Yes Exposure: UI UI was measured using an ordinal scale; participants rated the frequency of episodes of UI during the previous year (0 = never, 1 = ≤1 episode/month, 2 = 2–4 days/month, 3 = 2–4 days/week, 4 = 5=7 days/week).
Was the exposure measured in a valid and reliable way?	No UI was measured with a self-report scale.
Were confounding factors identified?	Yes Age, sex, years of education, hypertension, diabetes, MI, stroke, cancer, thyroid disorder, head trauma, BMI
Were strategies to deal with confounding factors stated?	Yes Examined crude associations of UI with confounders at baseline. Spearman’s rank correlation was used to test associations with age and education. Cox proportional hazard ratios to test association with adverse health outcomes. Regression models which controlled for age and sex.
Were the groups/participants free of the outcome at the start of the study (or at the moment of exposure)?	Yes Outcome: comorbidities (Parkinsonism) At the start of the study participants did not have Parkinsonism.
Were the outcomes measured in a valid and reliable way?	Yes Trained nurses performed a clinical examination and administered the Unified Parkinson’s Disease Rating Scale in which 26 items assessed four parkinsonian signs (gait or posture disturbance, bradykinesia, rigidity, tremor).
Was the follow up time reported and sufficient to be long enough for outcomes to occur?	Yes Eight-year follow up period was sufficient time to develop outcomes based on literature and clinical expertise.
Was follow up complete, and if not, were the reasons to loss to follow up described and explored?	No Loss to follow up was briefly described: 261 (10%) did not follow up because they died before the first follow up or had not been in the study long enough. Specific reasons for loss to follow up were not explicitly described or explored. There was <20% drop out rate which does not significantly impact the validity of the study.
Were strategies to address incomplete follow up utilized?	No 261 participants who were lost to follow up were excluded from analysis.
Was appropriate statistical analysis used?	Yes Used Cox proportional hazard ratios to test association with adverse health outcomes and regression models which controlled for age and sex.

Note. UI, urinary incontinence; MI, myocardial infarction; BMI, body mass index

Table 6.

Critical Appraisal of Case Control Studies

Joanna Briggs Institute Checklist Questions (case control studies)	Divani et al., 2011
Were the groups comparable other than the presence of disease in cases or the absence of disease in controls?	No Although the groups were comparable in terms of most characteristics (age, race, ethnicity, living arrangements, and general health, stroke subjects had more pain (37% vs. 29%, p=0.002), diabetes (29% vs. 17% p<0.0001), and hypertension (71% vs. 49%, p<0.0001) than non-stroke subjects.
Were cases and controls matched appropriately?	Yes 631 non-institutionalized individuals who had suffered a single stroke were matched with 631 controls based on age, gender and interview wave.
Were the same criteria used for identification of cases and controls?	Yes Stroke was defined as subjects who had a first-ever stroke in one of the interview waves between 1998 (4th interview wave) and 2006 (8th interview wave). Control subjects were randomly selected from a cohort matched for age (±5 years), gender and interview wave.
Was exposure measured in a standard, valid and reliable way?	No Exposure: stroke Self report in telephone and face-to-face interviews as part of the Health and Retirement Study.
Was exposure measured in the same way for cases and controls?	Unclear Telephone and face-to-face interviews. No explanation on what the indicator for stroke was.
Were confounding factors identified?	Yes Age, gender, interview wave, diabetes, hypertension, living arrangements, alcohol consumption, ethnicity, psychiatric problems, proxy respondent, pain
Were strategies to deal with confounding factors stated?	Yes Binomial and Poisson distribution were used to model the frequencies of each of the health problem outcomes (motor impairment, UI, sleep disturbance) with classical covariance analysis using generalized linear modeling of each health condition
Were outcomes assessed in a standard, valid and reliable way for cases and controls?	No Outcome: UI Self report of the involuntary loss of urine within the past 12 months in telephone and face-to-face interviews
Was the exposure period of interest long enough to be meaningful?	Yes The longitudinal sampling strategy ensured that the health condition developed after the subject had suffered a stroke.
Was appropriate statistical analysis used?	Yes Chi-squared and/or t-tests were used to provide initial unadjusted comparisons between stroke and non-stroke subjects. Classical covariance analysis using generalized linear modeling of each health condition was used to estimate the effect of stroke on each health outcome.

Note. UI, urinary incontinence

Although critical appraisal revealed that most included studies had several strengths, weaknesses were identified across most studies in key areas. The measurement of UI was a notable weakness across most studies. Nine studies^53–60,62 (90%) used self-report questions that were not psychometrically tested to assess UI. This can result in underreporting of UI and produce biased estimates. Only one study⁶¹ measured UI using the International Consultation on Incontinence Questionnaire, which has strong psychometric properties and generates valid and reliable scores.⁶³ No studies confirmed UI with additional measurements.

The measurement of comorbidities was a similar weakness found among included studies.^{53,54,57,59–62} (70%) assessed comorbidities with self-report interviews or questionnaires. Only one study⁵⁵ (10%) used measures that generate valid and reliable scores to assess comorbidities (i.e., the Unified Parkinson’s Disease Rating Scale). Only two studies^55,58 (20%) specified that clinicians performed a physical examination and used standardized instruments and validated protocols to assess comorbidities (i.e., Parkinsonism, sarcopenia). It remained unclear how one study⁵⁶ assessed comorbidities, as the authors reported that blood pressure, diabetes, and bone density measurements were taken at the hospital. Still, no details were provided about these measures (e.g., how blood pressure was taken, laboratory tests for fasting blood sugar or non-fasting blood sugar, hemoglobin A1C, fingerstick blood sugar, bone scan). Moreover, risk of measurement bias existed among these studies in that no study specified the qualifications of the individuals performing measurements. Studies described these individuals as professional interviewers,⁵³ trained professionals,⁵⁶ trained nurses,⁵⁵ and geriatric physiotherapists⁵⁸; however, no further detail was provided.

The included studies exhibited some common strengths. In terms of sampling, all but one study⁶² had clearly defined inclusion and exclusion criteria. All but three studies^58,60,62 described the participants and setting in detail. Included studies involved community-based samples, which decreased the risk of selection bias. All studies identified confounding factors, which mitigated the risk of history bias. Most studies^{53–55,57,59–61} (n = 7; 70%) accounted for confounding variables in adjusted analyses. The remaining three studies^56,58,62 only adjusted for certain confounders and did not provide a rationale for variable selection. All studies used appropriate statistics to quantify the strength of the association between UI and comorbidities.

Relevant data that were extracted that relate to the current review objectives are presented in Table 7, including significant comorbidities of community-dwelling older adults with UI, study outcomes, and affected physiological system.

Table 7.

Results of Individual Sources of Evidence

Author, year	Study outcomes related to comorbidities	Comorbidities of community-dwelling older adults with UI	Affected physiological system
Bresee et al., 2014	Heart disease (OR = 1.87; 95% CI [1.51–2.31]; p < .0001) and stroke (OR = 1.57, 95% CI = [1.18–2.08], p = .0018) had a higher prevalence of UI in unadjusted analysis. Heart disease remained significant in the adjusted analysis (OR = 1.38; 95% CI [1.08–1.76]; p = .01).	Heart disease	Cardiovascular
		Stroke	Neurologic
Brown et al., 1996	Stroke (OR = 1.9; 95% CI = [1.3–2.7]), diabetes (OR =1.7; 95% CI = [1.2–2.4]), and chronic obstructive pulmonary disease (OR = 1.4; 95% CI [1.1–1.9]) were associated with the prevalence of daily UI.	Stroke	Neurologic
		Chronic obstructive pulmonary disease	Respiratory
		Diabetes	Endocrine
Buchman et al., 2017	UI was associated with incident parkinsonism (HR = 1.07; 95% CI = [1.02–1.12]; p = .008).	Parkinsonism	Neurologic
Burti et al., 2012	UI was more common in individuals with diabetes (p = .022) and hypertension (p = .008).	Hypertension	Cardiovascular
		Diabetes	Endocrine
Divani et al., 2011	Stroke was significantly associated with UI (OR 1.56, 95% CI [1.17–2.08], p < 0.01) and remained significantly associated when accounting for time (OR 1.64, 95% CI [1.13–2.39], p < 0.01)	Stroke	Neurologic
Erdogan et al. 2019	Sarcopenia was significantly associated with UI when muscle mass was adjusted by weight (OR = 1.47; 95% CI = [1.03–2.09]; p = .034).	Sarcopenia	Musculoskeletal
Gerst et al., 2011	Men with prostate conditions were more than twice as likely to report urgency UI compared to those without prostate conditions (OR = 2.18; 95% CI = [1.52–3.14]; p < .0001).	Prostate conditions	Genitourinary
Park & Son Hong, 2016	BPH was significantly associated with UI in model 1 (OR, 2.73, 95% CI [1.47–5.10]), model 2 which controlled for age, BMI, and education (OR, 2.68; 95% CI, [1.42–5.07], and model 3 which controlled for HTN, DM, stroke, and depression (OR, 2.58; 95% CI [1.36–4.90])	Benign prostatic hyperplasia	Genitourinary
Smith et al., 2010	Hypertension, congestive heart failure, arthritis, depression, and anxiety were associated with a higher prevalence of UI: medical comorbidity (OR = 1.91; 95% CI = [1.57–2.32]; p <.05), depression (OR = 2.35, 95% CI [1.58–3.48], p<0.05)	Hypertension Congestive heart failure	Cardiovascular
		Arthritis	Musculoskeletal
		Depression Anxiety	Psychologic
Sohn et al., 2018	Cerebrovascular disease (OR = 2.02; 95% CI = [1.26–3.23]; p = .003) and arthritis (OR =1.44; 95% CI = [1.18–1.77], p < .001) were significantly associated with UI.	Cerebrovascular disease	Neurologic
		Arthritis	Musculoskeletal

Note. OR, odds ratio; CI, confidence interval; UI, urinary incontinence; HR, hazard ratio

Comorbidities of Community-Dwelling Older Adults with UI

The included studies revealed significant associations between UI and comorbidities across seven physiological systems (i.e., neurologic, cardiovascular, psychologic, respiratory, endocrine, genitourinary, and musculoskeletal). Comorbidities affecting the neurologic and cardiovascular systems were found to be most commonly associated with UI. Associations between the psychologic, respiratory, endocrine, genitourinary, and musculoskeletal systems and UI were less frequent, but still meaningful.

Neurologic Comorbidities

Five studies^{53–55,57,62} (50%) found significant associations between comorbidities affecting the neurologic system and UI. Four of the five studies evaluated UI as the outcome variable and found stroke^53,54,57 and cerebrovascular disease⁶² to be associated with UI. The remaining study examined UI as the exposure variable and found an association with Parkinsonism,⁵⁵ suggesting that UI could be an early sign of the development of this disease.

Cardiovascular Comorbidities

Of the three studies^53,56,61 (30%) that found significant associations between cardiovascular comorbidities and UI, two studies found a significant association between hypertension and UI.^56,61 In one of these studies, approximately 40% of the sample was taking diuretics to treat hypertension,⁵⁶ which can contribute to lower urinary tract symptoms.⁶⁴ Therefore, it was acknowledged that the association found may have been influenced by medications. The other study that found a significant association between hypertension and UI also found a significant association between congestive heart failure and UI.⁶¹ This finding suggests that UI may be associated with an aggregate effect of comorbidities rather than individual diseases. The remaining study found heart disease to be significantly associated with UI in multivariable analysis adjusting for age, race, ethnicity, and income.⁵³

Psychologic Comorbidities

Only one study⁶¹ (10%) found significant associations between psychologic comorbidities (i.e., anxiety and depression) and UI. These conditions were significantly associated with UI in bivariate analyses in which UI was examined as the outcome variable. This suggests that these mental health comorbidities may lead to the development of UI, although reasons for this remain poorly understood.

Respiratory Comorbidities

Only one study⁵⁴ (10%) found a significant association between respiratory comorbidities (i.e., chronic obstructive pulmonary disease (COPD)) and UI. COPD was identified as an independent factor associated with UI. This association remained significant after adjusting for smoking.⁵⁴

Endocrine Comorbidities

Of the two studies^54,56 (20%) that found significant associations between endocrine comorbidities and UI, both identified diabetes. One study found diabetes to be significantly associated with daily UI,⁵⁴ while the other study did not evaluate UI frequency.⁵⁶

Genitourinary Comorbidities

Two studies^59,60 (20%) found significant associations between prostate conditions (i.e., benign prostatic hyperplasia) and UI. One study included all UI subtypes⁶⁰ and one study focused on the urgency UI subtype.⁵⁹ In both studies, prostate conditions were found to be independently associated with UI and remained significant when controlling for other confounding factors.^59,60

Musculoskeletal Comorbidities

Three studies^58,61,62 (30%) found significant associations between musculoskeletal comorbidities and UI. One study found sarcopenia to be significantly associated with UI adjusted for weight.⁵⁸ The other two studies found arthritis to be significantly associated with UI, which remained significant in adjusted analyses.^61,62

Discussion

This scoping review included 10 studies identifying relevant comorbidities of community-dwelling older adults with UI across multiple physiological systems. The relatively small number of studies dedicated to UI and associated comorbidities among this population provides limited insight into causality, shared mechanisms, and directionality of relationships. Future research is needed to understand relationships between UI, comorbidities, and co-occurring symptoms to generate clinical phenotypes and improve the identification and management of UI.

Although connections between some comorbidities of community-dwelling older adults with UI identified in this review were not surprising (i.e., neurologic comorbidities, psychologic comorbidities, genitourinary comorbidities), others seemed less obvious. Approximately one-third of included studies identified musculoskeletal comorbidities (i.e., arthritis and sarcopenia) associated with UI. Reasons for this may include loss of muscle mass and skeletal malformations that can contribute to pelvic floor disorders. This can lead to UI if the pelvic floor muscles are weak. Additionally, cough and dyspnea related to COPD can increase intra-abdominal pressure which can put stress on the bladder and further weaken pelvic floor muscles leading to UI.⁶⁵ These associations may not be known to clinicians, as evaluation of the pelvic floor is not routinely taught in clinical training.⁶⁶ Associations between UI and comorbid conditions such as hypertension, congestive heart failure, heart disease, and diabetes may also not be obvious. Underlying shared mechanisms may play a role, as well as other factors, including the aggregate effect of multiple comorbidities, how treatment for one condition affects another, and changes in physical and functional status throughout the life course. Understanding relationships between comorbidities and UI can improve clinicians’ awareness of the interconnectedness of physiological systems and facilitate holistic assessment strategies.

The directionality of relationships between comorbidities and UI remains elusive in the literature. Medications used to treat certain conditions (e.g., diuretics for hypertension or heart failure) may lead to UI.⁵⁶ Only one study included in this review noted that diuretic use among participants might have influenced the association between hypertension and UI.⁵⁶ However, a growing body of literature suggests that diuretic use is associated with other lower urinary tract symptoms, including frequency and urgency, but not with UI.^36,64,67 Despite this evidence, the perception that diuretics may provoke or worsen UI may cause patients to avoid taking these essential medications to treat cardiovascular disease.⁶⁸ Further research is needed to examine whether certain medications can initiate or exacerbate UI, or if shared mechanisms between certain comorbidities and UI may be the primary contributing factor.

Almost all studies in this review examined comorbidities as the exposure and UI as the outcome variable, indicating that certain comorbidities lead to the development of UI. However, these relationships may be bidirectional.¹⁹ Mental stressors can influence health throughout the life course and increase the risk for lower urinary tract symptoms, including UI, through changes in stress physiology.⁶⁹ For example, evidence suggests that exposure to childhood adversity increases the risk for lower urinary tract symptoms and UI in adult women.⁶⁹ Therefore, mental health conditions, such as anxiety and depression, may be risk factors for lower urinary tract symptoms, including UI. One study included in this review that investigated psychologic comorbidities examined anxiety and depression as exposure variables and found significant associations with UI.⁶¹ Reasons for this may include alterations in stress physiology over time, although this was not the focus of this study. Conversely, stress, anxiety, and depression can be consequences of UI in terms of reduced quality of life, negative self-worth, loss of relationships, social isolation, financial distress, and stigma.^19,20 This evidence supports the need to screen for UI when older adults present with symptoms of anxiety or depression. This can be facilitated and standardized through the development of evidence-based holistic care guidelines that account for multiple conditions across physiological systems, as identified by this review.

In addition to the impact of mental stressors on physical health, physiologically, research has investigated the association between autonomic nervous system dysfunction and UI by measuring heart rate variability.^70–76 The autonomic nervous system regulates many involuntary body processes, including blood pressure, heart rate, respiration, blood sugar,⁷⁷ digestion, and bladder function.⁷⁸ Specific to bladder function, the sympathetic nervous system controls bladder storage and the parasympathetic nervous system controls bladder emptying within the autonomic nervous system. Therefore, it is thought that dysfunction can lead to UI.^74,79 Measuring heart rate variability is a reliable, non-invasive way to assess the action of these systems and evaluate for dysfunction.⁷⁹ Prior research that used heart rate variability to evaluate the relationship between autonomic nervous system dysfunction and UI found differences in heart rate variability parameters among patients with urgency UI and overactive bladder syndrome (i.e., urinary frequency, urgency, nocturia) compared to patients without urinary symptoms.^{70,71,73,75,76} Although this evidence supports a linkage between UI and autonomic nervous system dysfunction, these findings are limited to one UI subtype (i.e., urgency). The relationship between autonomic nervous system dysfunction and other UI subtypes (i.e., stress UI and mixed UI) remains unclear.⁸⁰ Given the physiology of the autonomic nervous system and the existing evidence, it is reasonable to posit a connection between autonomic nervous system dysfunction and UI. However, further research is needed to determine relationships between autonomic nervous dysfunction and different UI subtypes, especially in the context of community-dwelling older adults. From a life course perspective, it is more common for older adults to have mixed UI than urgency or stress UI in isolation.³ Of the studies included in this review, more than half did not specify the type of UI studied.^{53–55,57,61,62} Future research should clearly define the type of UI studied to understand the association with autonomic changes and the development of comorbidities throughout the life course.

Autonomic nervous system dysfunction has been linked to several comorbidities among community-dwelling adults with UI identified by studies included in this review, including stroke,⁸¹ Parkinsonism,⁸² heart failure,⁸³ hypertension,^56,61 COPD,⁵⁴ and diabetes.^54,56 Although most studies included in this review examined comorbidities as the exposure and UI as the outcome variable (i.e., indicating comorbidities precede UI onset), these relationships may not be one-directional. For example, UI can occur after stroke due to brain and nerve damage, impacting bladder control.⁸⁴ Other stroke-related factors can contribute to and worsen UI, such as functional limitations, cognitive impairment, and caregiver dependence.⁸⁴ Conversely, UI may be an early indicator of declining health status.⁸⁵ In a study of hospitalized and clinic patients with heart failure (n = 296), participants with late-stage heart failure were almost three times as likely to have UI compared to those in early-stage heart failure.³⁶ UI can occur early in the course of Parkinsonism, prior to developing motor symptoms, including gait disturbance and tremor.⁵⁵ Further, comorbidities often have overlapping signs and symptoms. For example, existing evidence supports heart failure and depression can have mutual signs such as decreased heart rate variability^86,87 and symptoms of fatigue, sleep disturbance, and reduced mood. Other comorbidities such as stroke, Parkinsonism, COPD, and arthritis may also share these symptoms. Additionally, UI can be associated with these symptoms⁷¹ as well as decreased heart rate variability,⁷¹ which supports potential shared mechanisms among these conditions. Therefore, autonomic nervous system dysfunction may be a shared mechanism between UI and several comorbidities. Further research is needed to investigate the influence of the autonomic nervous system on UI and comorbidities with analyses controlling for potential confounders such as sociodemographic characteristics, functional status, and medications. Including these confounders in analyses will build on knowledge gained through this review and generate detailed clinical phenotypes to guide assessment and management on a more granular level.

To advance the understanding of shared mechanisms between UI and comorbidities among community-dwelling adults with UI, research must continue to be done globally. The studies included in this review were conducted across four countries (i.e., the United States, Brazil, Turkey, and Korea). Although this highlights the worldwide prevalence of UI, this does not capture the global impact. According to estimates from 2018, 423 million (21.6%) people worldwide were affected by UI.⁴¹ This number has consistently increased over time and will continue to rise, especially given the growth of the aging population.⁴¹ The regional burden of UI was estimated to be greatest in Asia, with increasing incidence in Africa and South America.⁴¹ Given differences in genetic and environmental risk factors across countries, differences in comorbidities are expected. Therefore, expanding knowledge of comorbidities among community-dwelling older adults with UI may identify these differences and generate implications for clinical practice on a global scale.

Many of the included studies did not include racially and ethnically diverse samples, as most studies that reported race and ethnicity data included samples of mostly White participants. Only two studies included participants of more than two races, with participants of minority races comprising only a small percentage of the samples.^53,56 Available evidence has shown that UI prevalence differs by race and ethnicity^88,89 and racial and ethnic disparities exist in UI care in terms of quality and timing of care.^90–92 Specifically, prior studies have shown that Black men received fewer and more delayed procedures to treat UI than White men⁹⁰ and Latina women had the longest delays in care for UI compared to Black and White women.⁹¹ Differences in UI prevalence and disparities in care give rise to the need for research with more diverse samples to examine comorbidities associated with UI by race and ethnicity to guide holistic, equitable care.

Implications

The results of this scoping review have several implications for research and clinical practice. Results of this review provide foundational knowledge for symptom-based research aiming to develop well-defined clinical phenotypes for community-dwelling older adults with UI. Knowledge of comorbidities of community-dwelling older adults with UI illuminates what symptoms may comprise these patients’ clinical phenotypes. Associated symptoms can be derived through clinical domain expertise or qualitative research involving older adults with UI.

In terms of clinical practice, knowledge about relationships between comorbidities and UI may prompt clinicians to employ routine screening for UI. Evidence supports UI as an early indicator of neurological disease^37,55 and UI may also precede the onset of conditions affecting other physiological systems. Research has shown that patients prefer clinicians to initiate discussions about UI¹⁰; however, these discussions seldom take place.¹² Knowledge generated from this review may allow clinicians to recognize patients with certain comorbidities at increased risk for UI to facilitate these conversations and ameliorate barriers to care.

Further, results of this review support the need for evidence-based holistic care guidelines, which can be implemented by generalists caring for older adults with UI and multiple comorbid conditions. These guidelines may include referrals to specialists (e.g., mental health, neurology, cardiology, endocrinology, urology, physical therapy), when management extends beyond generalists’ scope. If referrals are made, collaboration is essential to avoid fragmented care and promote holistic management of community-dwelling older adults with UI. Some countries (e.g., United Kingdom and the Netherlands) promote this collaboration through care models that involve a specialist continence nurse in the initial assessment and management of UI in primary care and specialty settings.^93,94 These care models emphasize comprehensive assessments and have been found to be effective in improving symptoms⁹⁴ and reducing health care costs.⁹³ A specialist continence nurse can coordinate care between generalists and specialists. Results of this review support the need to integrate comorbidities into the assessment of older adults with UI and adopt these collaborative models globally.

Screening for UI when patients present with other conditions is an understudied area of research. Future research should investigate these underlying relationships to determine causal mechanisms and improve comprehensive care. To examine these relationships, future studies should assess UI in ways that produce more valid and reliable measurements. Bladder diaries, 24-hour pad testing, physical exam, and urodynamic testing can confirm and quantify UI⁹⁵ to mitigate the risk of biased reporting and produce more reliable estimates. Although bladder diaries are also self-reported, this method offers a more systematic way of collecting data on the day or week level, which can be more precise than recall over an unspecified period. Although objective data may be obtained through 24-hour pad testing, physical examination, and urodynamic testing, the practicality and utility of these measurements must be considered. These measurements may not yield accurate data as there is still a degree of subjectivity in 24-hour pad testing and physical examination. Additionally, it may not be feasible to perform urodynamic testing, especially in studies that involve large sample sizes. Future studies should consider using tools to assess UI that have strong psychometric properties (e.g., the International Consultation on Incontinence Questionnaire) in combination with bladder diaries to enhance the validity and reliability of UI measurement.

Limitations

This scoping review is not without limitations. In terms of the included literature, most studies used self-report questions that were not psychometrically tested to measure UI. Further, the definition of UI varied, and a range of terminology was used in self-report questions. Almost all studies included in this review were cross-sectional, which limits the ability to infer causality. Only one included study employed a prospective cohort design and utilized longitudinal data to investigate the development of comorbidities among older adults with UI over time. Regarding sampling, included studies involved samples of mostly White female participants, which impedes generalizability to male and racially and ethnically diverse populations.

It is possible that some relevant studies may have been missed as the search was limited to three databases and excluded articles not published in English. Given that this review focused on community-dwelling older adults with UI, findings may not be generalizable to older adults in other settings, such as nursing homes, hospitals, or younger populations. Lastly, this review focused on comorbidities associated with UI and not symptoms. Although studying symptoms may lead to a more granular analysis and robust understanding of the interdependence of physiological systems, current symptom-based literature involving patients with UI primarily focuses on urological symptoms.^96–98 Therefore, studying comorbidities was more appropriate for this current scoping review’s objectives to gain insight into comprehensive conditions affecting community-dwelling older adults with UI to provide a basis for future symptom-based research.

Conclusion

With the growth of the aging population, it is expected that the number of community-dwelling older adults with UI will continue to rise.⁴¹ There is an increasing need to shift from siloed specialty-specific health care to an integrated interdisciplinary approach.⁵ This approach warrants evidence-based holistic care guidelines informed by clinical phenotypes that account for multiple conditions. Results from this review highlight comorbidities of community-dwelling adults with UI across multiple physiological systems and provide foundational knowledge for future symptom-based research to build clinical phenotypes. Additionally, comorbidities and UI are interrelated, and future research is needed to understand shared mechanisms and directionality of relationships throughout the life course. Increased knowledge of these relationships can increase clinicians’ awareness of the need to screen for UI when patients present with other conditions. Future research should investigate the utility of routine screening among diverse populations and integrating comorbidities into collaborative care models to foster holistic, equitable care and improve outcomes.

Highlights.

• Older adults with urinary incontinence have comorbidities and co-occurring symptoms.

• Comorbidities and urinary incontinence are interrelated.

• Identifying comorbidities is a critical first step to building clinical phenotypes.

• Clinical phenotypes are essential to inform evidence-based holistic care.

• A shift from specialty-specific health care to an integrated approach is warranted.