Including the patient’s oral health perspective in evidence-based decision-making

Abstract

Background

How to approach the assessment of patient-perceived oral health is of fundamental importance for the evaluation of clinical and public health interventions because the patient’s assessment should be used as an adjunct to objective dental findings in order to decide which interventions work.

Aim

This review article aims to provide an overview of the principles, current status, and future outlook for how a patient’s oral health perception can and should be assessed.

Review findings

The hierarchical position of dental patient–reported outcomes, oral health–related quality of life (OHRQoL), and dental patient–reported outcome measures within the hierarchical concepts of quality of life and its component, health-related quality of life, is presented. The Mapping Oral Disease Impact with a Common Metric project is outlined as an international effort to describe current approaches to standardize the measurement of oral impact using the four OHRQoL dimensions of oral function, orofacial pain, orofacial appearance, and psychosocial impact.

Conclusion

Ultimately, these four dimensions of OHRQoL provide a practical and psychometrically solid way to collect and analyze OHRQoL data for all oral diseases in all settings, and eventually for all treatments through the use of a standardized, universal measurement tool. This universal impact metric capturing the patient’s oral health perspective is the key to moving evidence-based dentistry and value-based oral health care forward.

Introduction

The dental patient’s oral health perspective can be characterized by dental patient–reported outcomes (dPROs), with oral health–related quality of life (OHRQoL) being the most widely used concept. It can be assessed with dental patient–reported outcome measures (dPROMs). The most widely used instrument to measure dPROMs is the Oral Health Impact Profile (OHIP).

This review article aims to provide an overview of the principles, current status, and future outlook for how patients’ oral health perception can and should be assessed. The hierarchical position of dPROs, OHRQoL, and dPROMs within the hierarchical concepts of quality of life and its component, health-related quality of life (HRQoL), will be presented next. A short characterization of an international effort, the Mapping Oral Disease Impact with a Common Metric (MOM) project, will follow. The MOM project intends to standardize oral impact measurement using the four OHRQoL dimensions of oral function, orofacial pain, orofacial appearance, and psychosocial impact. Finally, synthesizing the present situation of the oral health impact measurement and the future outlook, the article ends by concluding that a universal oral health impact metric capturing the patient’s oral health perspective is the key to moving evidence-based dentistry and value-based oral health care forward.

Principles, current status, and future outlook for assessing patients’ oral health perception

Quality of life

Quality of life (QoL) is a concept that includes everything that contributes to a person’s general well-being [1]. There is universal agreement that QoL is multidimensional, but experts disagree on which dimensions make up this complex concept. For decades, this challenge of standardizing the concept has been recognized by other QoL experts [2, 3]. The outcome of attempts to conceptualize this vague idea have resulted in variations in sets of dimensions, e.g., the Centers for Disease Control and Prevention (CDC) associates eight dimensions with the QoL construct [4], whereas the World Health Organization (WHO) designates only six [5]. This has fostered difficulties for QoL researchers and has led to criticism of QoL instruments for either missing core dimensions or including dimensions that are not seen as important [3].

Health-related quality of life

Regardless of the disagreement on some QoL dimensions, it is universally endorsed that health is undoubtedly one of them. Health is such an integral part of one’s overall well-being that when it changes, general QoL tends to follow suit. The WHO defines health as “a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity” [6]. The dimension of QoL focused on general health can be described as health-related quality of life (HRQoL). Intuitively, health professionals are interested in measuring HRQoL because it relates directly to patient health and well-being. Like QoL, HRQoL is multidimensional, and experts face similar difficulties when attempting to determine a definitive catalog of its dimensions. The CDC and WHO note four dimensions; healthcare educators and professionals use the biopsychosocial model, which has three dimensions; and the Short-Form Health Survey (SF-36), one of the most commonly used instruments to measure HRQoL, uses only two dimensions [7, 8].

Oral health–related quality of life

Just as the broad scope and focus of QoL are broken down into components such as HRQoL, further classifying the many elements of HRQoL into more specific areas of health, e.g., oral health, is useful. Oral health has been closely linked to overall health and well-being. Dental patients can experience 1323 different oral diseases, many of which are highly prevalent and chronic in nature [9]. Due to the unique problems and needs of this patient population, a more focused HRQoL classification was necessary. Oral health–related quality of life (OHRQoL) is an important component of HRQoL and is an essential area of focus for oral health professionals and researchers. Oral health care providers are interested in measuring OHRQoL to help identify which dental treatments decrease oral disease the most. When health care providers and researchers understand how a variety of treatments affect the burden patients experience due to a disease, i.e., disease impact, they can use this information to select, together with their patients, the treatments that reduce the patient burden the most.

Dimensionality—the key to measuring the patient’s oral perspective

Like other QoL constructs, OHRQoL is multidimensional, and deliberation around OHRQoL dimensionality has been widespread. In 1994, Slade and Spencer [10] used Locker’s model of oral health, based on the WHO’s International Classification of Impairments, Disabilities, and Handicaps [11], now the WHO’s International Classification of Functioning, Disability and Health [12], as a framework to determine seven domains, or dimensions, of OHRQoL [13]. Those dimensions were used to develop an OHRQoL measurement tool, OHIP, and its short-form, which have been globally utilized by researchers and clinicians. Since then, subsequent studies, including exploratory and confirmatory factor analyses, have condensed the construct further into four clinically intuitive OHRQoL dimensions: oral function, orofacial pain, orofacial appearance, and psychosocial impact [14, 15]. The impact that every oral disease has on a patient can be captured well by one or more of these four OHRQoL dimensions. In contrast to many other OHRQoL instruments, the four dimensions of OHRQoL are captured well by OHIP and its short-form versions, providing researchers and clinicians with a clinically intuitive and psychometric tool for standardized measurement of the construct in many settings.

Patient-reported outcomes

Dentistry has historically been fixated on clinical, disease-oriented findings such as periodontal probing depths, clinical attachment, and number of missing teeth. These clinician-assessed outcomes are objective in nature and are used to determine the patient’s oral health status. As is true within the medical field, dentistry has traditionally focused on clinical outcomes while being resistant to using the patients’ perceived health status, which can inform care plans and treatment outcomes. More recently, the importance of assessing the patient’s perceived health report as a complementary component to clinical assessment to fully capture disease impact has gained momentum with researchers and oral health professionals [16].

A patient-reported outcome (PRO) is a report made by the patient regarding their own health status without interpretation by the provider [1]. The term PRO encompasses anything a patient reports about their health status and includes characteristics such as HRQoL, functional status, disease symptoms, health behaviors, and patient experience [17]. Because dental patients report problems specifically related to their oral health, it is important to note that PROs, which broadly cover all aspects of health, contain the subset of dental patient–reported outcomes (dPROs), which focus only on oral health. Like PROs, dPROs include characteristics such as the four dimensions of OHRQoL, which also include symptoms of oral diseases, oral health behaviors, and dental patient experience (Fig. 1). Some dPROs, such as symptoms of oral diseases, for example, do not capture the impact of oral diseases, but they can be helpful for describing the manifestations of the disease itself. For example, bleeding gums are a symptom that the patient may report, a subjective representation of periodontal disease itself, but they do not actually make the impact on the patient’s orofacial pain, orofacial appearance, oral function, and/or psychosocial well-being.

Fig. 1.

Conceptual framework: oral health–related quality of life (OHRQoL), an important dental patient–reported outcome (dPRO) comprised of four dimensions, as a component of the broader constructs health-related quality of life (HRQoL), quality of life (QoL), and patient-reported outcomes (PROs)

The four dimensions of OHRQoL capture the patient experience better than alternative dimensional structures for OHRQoL. As explained above, OHIP’s original seven-domain (dimension) structure has lost its validity because it was grounded on a model of the WHO’s International Classification of Impairments, Disabilities, and Handicaps from 1980 [11]. This classification has now been replaced by a newer conceptual framework. Since 2001, the WHO’s International Classification of Functioning, Disability and Health (ICF) has been the international standard for describing and measuring health and disability [12]. Presently, several studies support OHRQoL’s seven-dimensional structure [16, 18,19,20,21,22,23].

Dental patient–reported outcome measures

A dental patient–reported outcome measure (dPROM) is an instrument, questionnaire, scale, or survey that captures dPROs and expresses them numerically as a score [9]. Dental patient-reported outcome measures assessing dPROs are analogous to patient–reported outcome measures (PROMs) assessing PROs [9]. In fact, the Patient-Reported Outcomes Measurement Information System (PROMIS) represents a set of standardized measures for general-health PROs. Even though PROMs such as SF-36 can also assess the impact of oral diseases on dental patients, dPROMs such as OHIP are better suited for this purpose because their content specifically assesses a patient’s oral health experience [9, 24]. For example, questions in PROMs that assess PRO physical functions, such as “Are you able to do chores such as vacuuming or yard work?”, hold little relevance for patients suffering from oral diseases [9]. Also, dPROMs are more discerning regarding changes due to dental treatments compared to the less specific PROMs [24].

Classification of dPROMs

Dental patient–reported outcome measures are further divided into two groups (Fig. 2). Generic dPROMs, such as OHIP, are applicable across all oral health conditions, whereas disease-specific dPROMs, such as the OHRQoL measure of oral submucous fibrosis, are applicable to one, or a group of, related oral diseases [16]. Several dPROMs are available, and each instrument measures a set of dPRO dimensions. To date, extensive systematic reviews have revealed 53 oral health–generic [16] and 102 oral health–specific dPROMs [22]. Typically, dPROs are measured by more than one dPROM [16]. An example is the dPRO OHRQoL, which is measured by the dPROMs OHIP and Geriatric Oral Health Assessment Index (GOHAI), a frequently used 12-item instrument developed for elderly populations. It should also be noted that different dPROMs for children and adults exist. For example, GOHAI and OHIP measure OHRQoL in adults, while Child OHIP (COHIP) measures the same construct in children aged 8–15 years [16].

Fig. 2.

Classification of dental patient–reported outcome measures (dPROMs)

The Oral Health Impact Profile

The Oral Health Impact Profile is the most commonly used dPROM and is available in 5-, 14-, 19-, 20-, and 49-item versions [10, 25,26,27,28]. Evidence shows that OHIP-5 can assess about 90% of the information assessed with OHIP-49 [29]. This makes OHIP-5 appropriate for measuring OHRQoL in most settings, although more items are appropriate for looking into specific impairments [30]. It should also be noted that most OHIP versions have been translated into several languages, and their psychometric soundness has been evaluated [10, 25, 29, 31, 32].

Typical characteristics of a dPROM

Characteristics such as number of items, nature of response options, type of rating scale, and impact quality vary among dPROMs. Researchers use the following types of rating scales to measure dPROs [16, 19]: (a) continuous-adjectival, in which the response options have an order (ordinal scale) and are represented by adjectives or descriptors for each response option (e.g., GOHAI, OHIP); (b) continuous-numerical, in which ordered responses are represented by a numerical rating scale (e.g., Mandibular Function Impairment Questionnaire); and (c) categorical-adjectival, in which no order is present in the adjectives (e.g., Dental Impact Profile) [16]. It should be noted that the largest scale is a visual analog scale (VAS), which has a continuous scale ranging from 0 (“never”) to 100 (“always”) [19]. The minimum number of response options noted is two (e.g., Jaw Disability Checklist, a categorical scale) [16]. Ordinal-response scales typically present with five response options (e.g., OHIP-5) [16, 19].

It can be said that an oral health problem is best characterized by both its frequency and its severity/intensity. For example, a problem occurring frequently but with low intensity might be as important to a patient as a problem occurring less frequently but with high intensity [30]. Certain dPROMs, such as Oral Impact on Daily Performance (OIDP), assess frequency as well as severity of the impact of oral health problems [30]. Reissmann suggests that measuring the frequency of the impact is the best possible way to measure an oral health problem comprehensively and accurately [30]. For most dPROMs, all item responses are summed up to derive a total, or summary score, which characterizes the impact. For example, the OHIP-14 summary score can vary from 0 to 56, in which higher summary scores represent higher levels of impact on OHRQoL [16].

Recall period is another crucial feature of a dPROM used to ask the patient to recall how they perceived their oral health within a timeframe, such as the previous week or previous month. Over the years, OHIP has had variations of this feature, including 1-year, 1-month, and 7-day recall periods [30]. Waller and colleagues found that OHIP scores with a 7-day recall period were as reliable and valid as versions that used a 1-month recall period [33]. A 7-day recall period is also commonly used with PROMIS recommended measures [30]. In sum, a shorter recall period captures all impairments, including rapid short-term changes of oral health. Developers of dPROMs are expected to rigorously test dPROMs for the psychometric properties of reliability, validity, and dimensionality before they are used widely. This rigor also applies when they are cross-culturally adapted, as has been done for commonly used dPROMs such as OHIP [10, 25] and the Orofacial Esthetic Scale (OES) [34,35,36,37,38].

Comparison of dPROMs with disease-oriented outcome measures

Traditionally, dPROMs were used alongside disease-oriented outcome measures to capture the impact of diseases and treatments or interventions [39]. Due to the advantages and disadvantages of both physical outcome measures and perceived measures, or dPROMs, a dual outcome assessment is the best approach to use. Typically, dPROMs have better reliability than physical measures, which depend on several factors such as biological variations and the competency level of clinicians; dPROMs undergo rigorous statistical testing, and consequently, their reliability is reasonably stable across populations. Their administration does not require the presence of a clinician, and an individual can self-administer a dPROM at home, thus making data collection more cost-effective [39]. Hence, dPROMs can easily be applied in a wide range of clinical and community settings. Above and beyond the conceptual barriers regarding the value of patient-reported information, some clinicians and researchers are reluctant to use patient-reported measures because they expect a substantial amount of missing information. However, even lengthier dPROMs such as OHIP-49 have shown low nonresponse rates in previous studies [25, 31, 32, 40]. The dPROMs’ flexibility is crucial for assessing the impact of oral diseases in areas with provider shortages, such as rural communities.

In sum, dPROMs can be cost-effective, time-saving, and convenient to administer. While clinical measures concentrate on the state of the orofacial structure, dPROMs examine the oral health of patients in conjunction with their general health and well-being. However, dPROMs also have a few disadvantages [39]. First, score interpretation can be challenging and requires calibration as well as additional training of the clinician or other personnel. Scores need a frame of reference such as normative values. Additionally, because several dPROMs are available, choosing the most appropriate dPROM for a given situation is challenging. Here, too, knowledge of dPROMs would be helpful in making the best selection. Finally, despite some of the most commonly used dPROMs such as OHIP and OES having already been translated into several languages and rigorously tested for psychometric properties, cross-cultural adaptation of dPROMs can present its own set of challenges. Most importantly, however, dPROMs capture what matters most, that is, the dental patients’ perspectives about the impact that diseases and treatments have on their OHRQoL, even though the development and evaluation of dPROMs require rigorous data collection and analysis prior to implementation.

Strategy for improved measurement of OHRQoL: a standardized approach

Dental patient–reported outcome measures are becoming increasingly important for dental research and practice, as they measure the impact of oral diseases best. Continued application of dPROMs will encourage increased involvement in treatment decisions. In the future, it can be expected that scores from dPROMs will be used to evaluate treatment in a standardized manner. With the use of evidence from similar populations, an individual’s pretreatment scores would be compared with established reference values or typical scores for target populations of the instrument [39]. Knowledge of the difference between pretreatment and post treatment scores would allow the clinician and the patient to assess treatment effectiveness. Another key estimate to be derived will be the minimal important difference (MID) or the magnitude of change. The MID is described as the smallest difference in domain scores that patients find beneficial and that would mandate a change in patient management in the absence of troublesome side effects and excessive cost [41]. Such estimates would be very challenging to measure using disease-oriented outcomes. Reissmann and colleagues have also demonstrated the conversion of OHIP scores into a numerical impact frequency, or the magnitude of impacts perceived by an individual [26]. Available dPROMs assess a limited number of dPROs, and they can all be characterized within the aforementioned four dimensions of OHRQoL. Thus, a universal set of dPROMs consisting of items targeting these four dimensions would be the ideal approach for measuring treatment effectiveness.

Future applications and recommendations

Continued efforts to develop more instruments to measure PROs and dPROs impair the pragmatic use of evidence-based dentistry. That said, it is encouraging to know that existing dPROMs measure one or a combination of the four dimensions of OHRQoL. Therefore, existing dPROMs can be used to inform the development of a standardized, universal dPROM. Since OHIP-5 has been shown to capture OHRQoL well, it is feasible to envision the purest form of a dPROM, which would include only one item per dimension for a total of four items. The OHIP-5 comes to this principle with one item for the dimensions of orofacial pain, orofacial appearance, and psychosocial impact, as well two items for the dimension of oral function. Ideally, this should be the only dPROM that oral health professionals need. Hence, oral health care researchers, educators, and providers would have one standardized tool to measure the impact of all oral diseases and the effects of different dental treatments on the patients’ OHRQoL. Long term, this universal dPROM could be used to derive reference values for all oral health conditions for several populations in terms of age and oral health status. Based on these values, treatments that reduce patients’ suffering or overall impact on OHRQoL would be the preferred treatment selected by providers and patients alike. Additionally, providers who use this information to guide their decision-making would likely be preferred by patients and other stakeholders such as insurance companies.

Implementation of this universal instrument within a focused setting, such as within one portion of a dental school, would allow for a small-scale trial of this standardized process. Next, implementation in other divisions, and eventually schoolwide use, would demonstrate the feasibility and usefulness of the universal tool. It would eventually be beneficial to perform these studies across diverse locations and populations to achieve a more holistic population database. Determining the differential diagnosis for 1323 oral diseases and multiple treatment options for each disease is challenging for most, if not all, oral health professionals. Based on the OHIP questionnaires and OHRQoL scores, this information can be converted into a single metric to be used more sustainably [42]. The act of gathering OHRQoL data that are currently available from published reports and putting that into a single database will allow dental providers and patients to determine what impact oral diseases have on patients. Past and ongoing research described below involve primary and secondary data collection and serve this purpose (Fig. 3).

Fig. 3.

Vision and process over time. OHRQoL oral health–related quality of life

Although pragmatic dPROMs are available today, such as the OHIP-5, which can be self-administered with only minimal burden on patients and health care providers, it is expected that technological advances will lead to broader application of dPROs. It is reasonable to estimate that, in the near future, all patient-reported information will be collected electronically. Mobile phones, tablets, and personal computers will allow this, regardless of whether patients use their own devices or whether the dental setting provides these devices for data entry. When and where the information is collected will also be flexible. Data can be collected before or after a dental appointment, when the patient is still in the health care setting, but equally important, posttreatment dPRO information can also be collected when the patient is at home. Conceptually, two types of data will be available when the evaluation of dental interventions is the target. In this situation, dPRO information that characterizes the patient’s suffering before a treatment (pretreatment scores) and dPRO information characterizing the patient’s suffering after the treatment (posttreatment scores) can be differentiated. Software will calculate the differences between pretreatment and posttreatment scores, representing the treatment-related changes in patient suffering, and will be used chairside to present findings numerically and graphically to the health care provider. The described approach presents the complete circle from collecting dPRO information, analyzing it, and presenting it back to the health care provider and patient to inform clinical decision-making.

Mapping Oral Disease Impact with a Common Metric project (MOM): alignment of published oral health impact information with the four OHRQoL dimensions

Efforts to move forward the vision of a standardized four-dimensional oral impact characterization across all settings and all oral diseases include the Mapping Oral Disease Impact with a Common Metric (MOM) project [42]. Rigorous collection and analysis of secondary data will ultimately improve the coverage, precision, feasibility, and score quality of oral disease impact mapping. Details of this process have been published elsewhere [43,44,45,46,47] and will be briefly discussed here.

A series of systematic reviews were conducted to capture the impact of oral disease on OHRQoL within the paradigm of its four dimensions. The targeted population for the reviews of the dPROs were based on the four-dimensions of OHRQoL. For example, patients with posterior tooth loss, edentulism, or a shortened arch would affect their oral function. Patients with pain anywhere in the orofacial region—for example, a toothache—would have orofacial pain. Patients who are impacted due to aesthetic problems, such as missing anterior teeth, would have effects on their orofacial appearance. Patients with more wide-ranging problems not specific to function, pain, or appearance would experience psychosocial impact. For example, halitosis does not cause pain, function, or appearance problems, but it can greatly affect a patient’s social interactions and relationships, causing psychosocial impact. Oral health conditions examined in each study within the given target population were organized into the four dimensions, or categories, to examine their overall impact on OHRQoL.

While the MOM project currently contains four-dimensional impact information for 189 adult and 22 pediatric dental patient populations, it can be expected that data for more dental patient populations will become increasingly available in the near future through published literature reports and also through large-scale data collection within treatment centers. The MOM project could be a hub for a continuously growing standardized body of data about oral disease impact in a continuously ongoing and updated process. Published data as well as unpublished data, such as data collected in dental treatment centers during regular dental practice, could be included.

MOM’s anticipated impact

Pragmatic use of evidence-based dentistry and clinical trial applications of MOM will allow dental practitioners and researchers to advance their knowledge of the impact of oral disease on individual and population levels. The need to consolidate OHRQoL into one metric is seen in the current state of inefficient use of multiple instruments.

Data collection on OHRQoL treatment effects, determination of the level of patient suffering, and use of this data among specific populations are just a few compelling examples of the impact this single metric would have. A single metric used universally could help determine specific treatment plans for patients and could help compare treatment efficacies for the dental provider. This information could then be further used to establish value-based care with public health significance and for the assurance of taxpayers [48]. For example, on a population level within a rural clinic, dental providers would be able to use these data to flag the groups of high-risk individuals and integrate the data within individualized care plans.

Conclusion

Ultimately, the four dimensions of OHRQoL—oral function, orofacial pain, oral appearance, and psychosocial impact—provide a practical and psychometrically solid way for oral health professionals to collect and analyze OHRQoL data for all diseases and eventually for all treatments through the use of a standardized, universal measurement tool. This ability to capture all OHRQoL data allows for the development of evidence-based guidelines that can be used to select the treatment modalities that reduce our patient’s oral health suffering most effectively. Oral health improvement will also lead to improvement of a patient’s general health and well-being. To achieve this, a single metric of oral health impact is essential for the future of value-based care and evidence-based dentistry.