Relationship between Age and Timely Placement of Vascular Access in Incident Patients on Hemodialysis

Abstract

Background and purpose

Placement of an arteriovenous fistula (AVF) prior to initiating dialysis can affect clinical outcomes for patients who subsequently initiate chronic hemodialysis treatments. Age-related variation in receipt of a functioning AVF prior to initiating dialysis is not well known. The purpose of this study was to examine age-related rates in use of AVF at the first outpatient dialysis treatment among U.S. incident patients on hemodialysis.

Findings

Among 526,145 identified, the use of AVF at the first outpatient dialysis treatment was lower in the youngest (<55 year) and oldest (≥80 year) vs. both 55–66 year and 67–79 year age groups. These findings persisted after adjusting for demographics, lifestyle behavior, employment and insurance status, physical/functional conditions, and comorbid conditions.

Conclusions

The presence of a functioning AVF at initial dialysis treatment varies by age. Modifying healthcare policy and/or expanding the role of the renal nurse practitioner should be considered to address this issue.

Introduction

Chronic kidney disease (CKD) is a significant public health problem affecting over 20 million people in the United States (Centers for Disease Control and Prevention [CDC], 2012; Rettig, Norris, & Nissenson, 2008). Based on the global contribution of CKD to premature mortality and morbidity, the World Health Organization (WHO) added CKD to its action plan for the prevention and control of noncommunicable diseases (WHO, 2010). Early detection and early nephrology care influence a multitude of public health consequences associated with psychosocial burdens and cost for patients with advanced CKD. Access to quality care for patients with advancing CKD may vary by race/ethnicity and geographic location (Yan, Cheung, et al., 2013). As such, arteriovenous fistula (AVF) placement prior to dialysis is an important indicator of pre-ESRD care and a Centers of Medicare and Medicaid (CMS) clinical performance measure (CPM) (Arbor Research Collaborative for Health & University of Michigan Kidney Epidemiology and Cost Center, 2013). Other performance measures monitored by CMS include the early management and surveillance of: (a) anemia, (b) mineral and bone disease, (c) infection control, and (d) kidney transplant list and waiting time, all of which contribute to the overall quality of care for patients with progressive CKD approaching the need for renal replacement therapy (RRT) (CMS, 2007).

The American Nephrology Nurses’ Association (ANNA, 2013) has taken the position that all patients requiring maintenance hemodialysis therapy should have a functioning permanent vascular access in place before initiating hemodialysis and that access placement be established in stage 4 of CKD. AVF is strongly associated with lower rates of infection and mortality (Wish; 2010). One of every two patients starting hemodialysis is over 65 years of age (United States Renal Data System [USRDS] 2013) and many factors that influence AVF success such as comorbidities, smaller vessel size, and atherosclerotic disease are more prevalent in older patients and could influence the successful and timely placement of an AVF.

Two key factors contributing to the increasing prevalence of CKD are an aging population and the increasing prevalence of the leading CKD risk factors, diabetes and hypertension (Erdem, Prada, & Haffer, 2013). People over 65 years of age comprise the fastest growing segment of the kidney failure population (Drawz, Babineau, & Rahman, 2012; USRDS, 2013). Both diabetes and hypertension are more common with increasing age (Yan, Norris, et al., 2013). Diabetes now accounts for an estimated 45% of new cases of kidney failure and hypertension for an additional 30% (USRDS, 2013). The implications of aging and ESRD for the national healthcare system are substantial and understanding the quality of pre-ESRD care for the elderly is a CMS priority.

This study was conducted to assess potential age-related differences in AVF placement. We hypothesized that older patients were less likely to have a functioning AVF in place at the first dialysis treatment. To test this, we performed a national population analysis to assess age-related differences in the use of AVF at the first dialysis treatment.

Methods

Data Sources and Study Population

The study included all new maintenance dialysis patients treated with renal replacement therapy living in any of the 50 states or the District of Columbia who were 18 years of age or older at the time of initiation of dialysis and entered in the United States Renal Data System (USRDS) between 2005 and 2010. USRDS is a national population-based registry that includes almost all U.S. patients with kidney failure. In 2005, the CMS ESRD Medical Evidence (ME) Report was revised to include information on pre-renal failure care received during the year prior to initiation of renal replacement therapy, so data collection included all patients who completed the revised ME form.

Study Variables

Data extracted from the USRDS included whether a patient used an AVF at the first outpatient hemodialysis session. Additional data was extracted to assess whether or not patients had received care by a nephrologist at least 12 months prior to starting dialysis, and whether or not patients had received care by a dietitian at any time prior to starting dialysis. Data on patient variables such as demographic characteristics, employment status, health insurance coverage, and comorbid conditions were also obtained from the USRDS. Data included gender, race and ethnicity, age at dialysis onset, lifestyle behavior (current smoking), health care access, health insurance status at the initiation of dialysis, physical/functional conditions, and various comorbid conditions (e.g., diabetes, hypertension, cardiovascular diseases, and cancer). Employment status at six months prior to ESRD was used as a proxy measure of access to health care. Each patient’s health insurance status was assigned to one of four categories: no insurance, Medicaid only, Medicare only, and other including employer-group only and/or two or more carriers. The study was approved by the Institutional Review Board (IRB) for Health Sciences Research at University of Virginia.

Statistical analysis

We assessed the differences in use of an AVF at the first outpatient dialysis session by comparing percentages of patients on hemodialysis with AVF across four age categories (< 55 years, 55–66 years, 67–79 years, ≥80 years of age). We examined the unadjusted odds ratios with logistic regression and then the odds ratios adjusted for patient characteristics, including demographics, lifestyle behavior, employment status and insurance, physical/functional conditions, and various comorbid conditions as listed in Table 1. The purpose of adjusted analysis was to assess whether the age related differences in use of an AVF at the first outpatient dialysis session persisted after accounting for the patient factors considered. To compare these four age groups, we present results of six pairwise comparisons by the order of age group: age groups of 55–66 years, 67–79 years, and ≥80 years compared with the youngest age group (<55 years). Then age groups of 67–79 years and ≥80 years compared with the second youngest age group (55–66 years), and finally the age group of ≥80 years compared with the third youngest group (67–79 years).

Table 1.

Patient Characteristics by Age Group

Patient characteristic	Age group
	< 55 years (n= 153,611)	55–66 years (n=154,126)	67–79 years (n=168,044)	≥ 80 years (n=83,275)
Age (years), Mean ±SD	43.4±8.9	60.7±3.4	72.9±3.7	84.1±3.4
Male sex (%)	59.2	56.0	54.5	54.2
Race/ethnicity (%)
Non-Hispanic white	37.3	50.0	61.9	72.8
Non-Hispanic black	40.0	30.5	22.6	15.7
Hispanic	16.9	14.1	10.6	7.1
Other	5.8	5.4	4.9	4.3
Employed at 6 months before end-stage renal disease (%)	66.3	79.4	91.3	93.7
Insurance coverage (%)
No insurance	18.3	8.4	1.0	0.6
Medicaid only	23.7	14.5	2.4	1.4
Medicare only	5.9	12.9	22.1	21.4
Other/combination	52.0	64.2	74.5	76.7
Current smoker (%)	9.8	7.8	4.4	1.6
Physical/functional conditions
Inability to ambulate (%)	3.4	6.6	8.7	11.1
Inability to transfer (%)	1.5	3.0	4.5	6.0
Needs assistance with daily activities (%)	6.1	10.2	14.1	19.0
Institutionalized - Nursing Home (%)	2.6	5.6	9.1	13.7
Comorbid conditions
Hypertension (%)	83.7	85.2	85.0	84.5
Diabetes (%)	46.9	63.7	56.8	39.9
Congestive heart failure (%)	19.2	32.4	39.7	45.7
Arteriosclerotic heart disease (%)	8.5	20.6	28.6	31.9
Other heart diseases (%)	8.4	15.5	21.3	25.3
Cerebrovascular accident/transient ischemic attack (%)	5.3	10.1	12.1	12.0
Peripheral vascular disease (%)	7.4	14.4	17.9	17.2
Amputation (%)	3.3	4.2	2.8	1.4
Chronic obstruction pulmonary disease (%)	3.7	9.2	12.9	12.4
Cancer (%)	2.7	6.6	10.6	12.1
Outcomea
AVF at first dialysis (%)	12.4	14.6	14.7	12.3
Receipt of nephrologist care at least 12 months before ESRD (%)	22.7	27.1	29.6	28.0
Receipt of dietitian care at any time before ESRD (%)	10.3	11.8	11.6	10.6

^aSample size varied: N= 526,145 for AVF, N= 491,992 for nephrologist care, and N= 450,626 for dietitian care.

Results

Patient Characteristics

Patient characteristics are presented in Table 1. Of the 559,056 patients reviewed, 153,611 (27.5%) were <55 years of age, 154,126 (27.6%) were 55–66 years of age, 168,044 (30.0%) were 67–79 years of age, and 83,275 (14.9%) were ≥80 years of age. Compared to older patients, those <55 years of age were more likely to be male, of a racial/ethnic minority, uninsured, less likely to be employed at 6 months before ESRD, and less likely to have most comorbid medical conditions.

Regression Analyses

Our logistic regression for AVF was restricted to the subset of incident patients on hemodialysis at the ESRD onset (N= 526,145). Unadjusted logistic regression analyses were first performed comparing the likelihood of using an AVF at first dialysis (Table 2) among the four age groups. Six pair-wise comparisons were made: 55–66 years, 67–79 years, and ≥80 years against the reference group (<55 years); 67–79 years, and ≥80 years compared to the 55–66 year-old group; and ≥80 years compared to the 67–79 year-old group. The likelihood of using an AVF at first dialysis was lower in the youngest and oldest groups (<55 years and ≥80 years) compared to the 55–66 and 67–79 year-old groups. The likelihood of using an AVF at first dialysis was similar in 55–66 and 67–79 year-old groups. Likelihood was also comparable between the <55 years and ≥80 years age groups. After adjusting for multiple patient characteristics, including demographics, lifestyle behavior, employment and insurance status, physical/functional conditions, and comorbid conditions listed in Table 1, the likelihood of using an AVF at first dialysis remained lower for the youngest and oldest groups (<55 years and ≥80 years) in comparison to the 55–66 and 67–79 year-old groups (Table 3). Sensitivity analyses revealed similar patterns between age and receipt of pre-ESRD nephrology care (N= 491,992) as well as age and receipt of pre-ESRD dietician care (N= 450,626) (data not presented).

Table 2.

Unadjusted Odds Ratios of Having an Arteriovenous Fistula at First Hemodialysis

Age Group	Odds ratio	95% CI	P value
55–66 vs. <55 years	1.21	(1.18–1.23)	0.000
67–79 vs. <55 years	1.22	(1.19–1.24)	0.000
≥80 vs. <55 years	0.99	(0.96–1.01)	0.313
67–79 vs. 55–66 years	1.01	(0.99–1.03)	0.354
≥80 vs. 55–66 years	0.82	(0.80–0.84)	0.000
≥80 vs. 67–79 years	0.81	(0.79–0.83)	0.000

Table 3.

Adjusted Odds Ratios of Having an Arteriovenous Fistula at First Hemodialysis

Age Group	Odds ratioa	95% CI	P value
55–66 vs. <55 years	1.18	(1.15–1.21)	0.000
67–79 vs. <55 years	1.16	(1.14–1.19)	0.000
≥80 vs. <55 years	0.98	(0.95–1.01)	0.173
67–79 vs. 55–66 years	0.99	(0.97–1.01)	0.208
≥80 vs. 55–66 years	0.83	(0.81–0.85)	0.000
≥80 vs. 67–79 years	0.84	(0.82–0.86)	0.000

^aAdjusted for the patient characteristics listed in Table 1.

Discussion

This is the first study to our knowledge that examined age-related differences in the use of an arteriovenous fistula at the initial hemodialysis treatment. Two specific groups were identified as having the lowest rate of AVF use at their first hemodialysis treatment, those <55 years of age and those ≥ 80 years of age. Our findings are consistent with those of Lilly et al. who reported lower odds of AVF placement among 195,756 adult incident hemodialysis patients older than 85 years of age (but not younger patients) as well as for women, blacks, Hispanics, and persons with diabetes, peripheral vascular disease, congestive heart failure, other cardiac disease, and underweight (Lilly et al., 2012). In contrast to our analysis, they examined patients with 6 months or more of prior nephrology care which may have pre-selected younger patients with insurance and may explain why they only found the lower AVF rates among older patients.

A similar analysis by Patibandla et al. found increasing age, female sex, black race, lower body mass index, urban location, certain comorbidities, and shorter pre-end-stage renal disease nephrology care were associated with a significantly lower likelihood of AVF being placed, even if it was not ready for use at the first dialysis treatment, among 118,767 incident hemodialysis patients ≥67 years of age (Patibandla et al., 2013). This study differed slightly from ours in that Patibandla et al. specifically looked at AVF being placed prior to dialysis, in contrast to AVF being used at first dialysis as examined in our analysis.

Study limitations include the cross sectional nature of the data that only allows us to assess relationships and not causal effects. In addition, a prior report of disagreement between information from the CMS Medical Evidence Report and Medicare physician claims for pre-ESRD care suggests the validity of CMS Medical Evidence Report is not clear (Kim, Desai, Chertow, & Winkelmayer, 2012). We examined pre-ESRD nephology and dietician care and found results similar to use of an AVF at initial dialysis, recognizing that timing of pre-ESRD care is inherently less definitive than use of an AVF at dialysis. Finally, not all patients may be good candidates for an AVF (Gomes, Schmidt, & Wish, 2013), but that should not prevent the renal community from striving to meet Healthy People 2020 goals for pre-ESRD care (USRDS, 2013).

The recommendations from our study include the need for promoting more universal insurance coverage such as expanded Medicaid and similar coverage for uninsured as should be provided with the new Affordable Care Act (Health Resources and Services Administration, 2011). In addition, prospective studies are needed to examine specific interventions at provider and patient/family levels that may increase access to timely quality care for patients with advanced CKD.

Implications for nephrology nurses

These findings should be a reminder to nephrology nurses, as members of the pre-ESRD and ESRD patient care team and, in some cases, primary care providers, to not only maintain diligence in facilitating quality pre-ESRD care but to be cognizant of the additional risks that exist for younger (<55 years) and older (≥80 years) patients related to obtaining an AVF for use at the first dialysis treatment. Working closely with social workers and family to address key socio-demographic issues may be important for engaging and motivating many patients. Strategies to enhance care coordination between primary care providers and the CKD/ESRD team should be explored by the all members of the health care team, including nurses and nurse practitioners. There is growing recognition and acceptance across multidisciplinary programs that nurse practitioners can make a positive contribution to healthy outcomes through an expanded role in working with public health agencies, community-based organizations (CBOs), and in-patient units. Polkinghorne et al. reported an increase in AVF placement from less than 50% to 65% following the introduction of a multifaceted intervention that included a vascular access nurse coordinator and an algorithm to prioritize surgery (Polkinghorne, Seneviratne, & Kerr, 2009). The present findings of both low rates of AVF use at the first dialysis treatment and disparities of AVF use across age groups should prompt a call to action by ANNA for nurses to more aggressively pursue a substantive leadership role on the CKD/ESRD team. Initiatives may include the use of nurse practitioners and/or clinical nurse specialists in CKD clinics as suggested by Davis and Zuber (2013). A joint initiative between ANNA and the American Society of Nephrology and/or Renal Physicians Association may help to address the issue of ensuring the highest quality of care for patients with advanced CKD.

Biographies

Rubette Harford, RN, MSN, is a PhD candidate in the Hahn School of Nursing and Health Science at the University of San Diego, San Diego, CA, USA.

Mary Jo Clark, MSN, PhD, is a Professor in the Hahn School of Nursing and Health Science at the University of San Diego, San Diego, CA, USA.

Keith C. Norris, MD, is a senior faculty member, Division of General Internal Medicine and Health Services Research, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA

Guofen Yan, PhD, is a faculty biostatistician, School of Nursing and Department of Public Health Sciences, School of Medicine, University of Virginia, USA. guofen.yan@virginia.edu