Determinants of patient preferences for total knee replacement: African-Americans and whites

Osteoarthritis (OA) is a highly prevalent and disabling disease, and the lifetime risk of developing knee OA is one in two [1‐3]. When conservative therapies no longer provide lasting pain relief, total knee replacement (TKR) becomes a very effective treatment option [4]. Despite its efficacy, there are marked racial disparities in the utilization of TKR. Using Medicare claims data, it has been estimated that the annual rate of TKR was 4.84 per 1000 among African-American (AA) women, compared to 5.97 per 1000 among white (WH) women [5]. The rate for AA men (1.84 per 1000) was also lower than that for WH men (4.82 per 1000). Analyzing Medicare data from other time periods and data from other national databases have elicited similar findings [5‐8].

Reasons for racial disparities in TKR utilization rate are complex and involve patient-level, provider-level, and system-level factors [7]. Patient preference has emerged as a key factor, however. It is a strong predictor of time to receipt of a first total joint replacement [9]. Patient preference in joint replacement may also vary by race, sex, and other sociodemographic factors [10‐16]. In studies of veterans with advanced knee or hip OA, AAs were consistently less willing to consider joint replacement compared to WHs [10‐13]. In a focus group study of AA patients’ attitudes and preferences in arthritis care, AAs expressed preferences for natural remedies and against undergoing surgery [17].

Patient preference is largely an attitudinal disposition [7]. According to the expectancy-value model, attitudes arise spontaneously and inevitably as we form beliefs about an object [18]. Our overall attitude towards an object is determined by the subjective value of the object’s attributes in relation to the depth of the association [18]. Hence, racial differences in treatment preferences in TKR are likely due to varying beliefs or opinions about the procedure and the healthcare system. Studies have shown racial variations in knowledge and expectations of joint replacement [11, 19‐21]. WHs are more likely to believe that TKR is efficacious and are more likely to be familiar with the procedure than AAs [11, 20, 21]. AAs are more likely to expect surgical complications [11, 21]. AAs are also less likely to be satisfied with their communication with orthopedic surgeons than WHs [22].

Moreover, studies have investigated some of the correlates of willingness to undergo joint replacement. Patients’ perceptions of appropriateness of surgery and of high efficacy and acceptable risks when undergoing joint replacement are all strongly associated with willingness to consider the procedure [16, 20]. Discussing the procedure and receiving a recommendation from a physician may also determine willingness to undergo joint replacement [15, 20]. High trust in physicians may also increase willingness [20]. Despite such evidence, the specific socio-cultural beliefs that impact patients’ willingness to consider TKR as a treatment option, by patient race, remain unclear, as do the factors that explain racial differences in treatment preferences in TKR.

The primary objective of this study is to examine the roles of patients’ knowledge of TKR, beliefs about TKR, attitudes towards TKR, attitudes towards providers, and attitudes towards the healthcare system, in determining willingness to undergo TKR, by patient race. The secondary objective is to determine which of these factors could mediate racial differences in willingness to undergo TKR.

Participants were recruited from the University of Pittsburgh and the Veterans Affairs (VA) Pittsburgh Healthcare System clinics. They were also sought through mailings and local advertisements. The recruitment methodology has been previously reported [23]. The study was approved by the University of Pittsburgh and VA Institutional Review Boards. Informed consent was obtained from all participants in the study.

Inclusion criteria included: AA or WH race, age ≥50 years, presence of chronic frequent knee pain [24], moderate-to-severe knee OA based on Western Ontario McMaster Index (WOMAC) summary score ≥39 [25], radiographic evidence of OA (i.e., Kellgren-Lawrence grade ≥2) [26], and presence of knee OA according to American College of Rheumatology [27] criteria. Exclusion criteria included: history of major joint replacement, terminal illness, inflammatory arthritis, or dementia. Patients participated in a face-to-face interview.

Participants included 514 WH and 285 AA patients with knee OA. AA participants were younger and more likely to be unemployed or disabled (Table 1). At screening, they also had higher WOMAC total, higher PHQ-9 depression, and lower SF-12 physical health scores.

In this large sample of AA and WH patients with knee OA, we found that determinants of patient preference for TKR differed between AAs and WHs. For AAs, better understanding of the procedure, a shorter hospital course, less post-surgical pain and walking difficulty, favorable expectations of surgery, less religiosity, and trust in physicians significantly influenced patient willingness to undergo TKR. On the other hand, favorable expectations of surgical outcomes, trust in healthcare, discussion with a physician, and not having received surgical referral were significant predictors of willingness among WHs. After controlling for socio-demographic and clinical factors, AAs were still much less willing to consider TKR surgery compared to WHs. Comprehending the process and outcomes of undergoing TKR attenuated this racial difference in patient preference.

Our study has various distinguishing characteristics from previous studies that examined racial differences in OA patients’ treatment preferences. Early studies showed that AAs were less willing to consider joint replacement than WHs based on surveys of male veterans with knee OA [12, 13]. Subsequent studies had similar findings based on surveys of patients recruited from community-based clinics in Texas [20, 37] and North Carolina [21]. In contrast, our study surveyed patients regularly treated at academic facilities, the VA and community-based clinics. Hence, we were able to assemble a cohort of OA patients who differ in regards to gender, socioeconomic status and access to care. Several studies have also explored determinants of treatment preferences for joint replacement [15, 16, 20, 21]. These studies focused on the roles of socio-demographic variables and patient knowledge of joint replacement, but minimally examined the roles of certain variables, including social support, religiosity and/or utilization process items. Finally, while previous studies merely controlled for patient race in their examinations of determinants of treatment preferences [12, 20, 21], our study is the first to identify specific determinants of the willingness of patients with knee OA to undergo TKR, by patient race.

Finding that good understanding of joint replacement and minimal perceptions of pain and difficulties after surgery were determinants of willingness to undergo TKR among AAs is consistent with previous OA studies [12, 16, 20]. Albeit, the North Carolina study [21] found that perceptions of joint replacement outcomes were not significantly associated with willingness to undergo knee or hip replacement surgery. Regardless, better knowledge of the process and outcomes of joint replacement seems to also minimize the racial difference in patient preference for the procedure.

In similar fashion, the knee OA VA study suggested that differences in expectations of hospital course, pain and function after joint replacement fully mediated racial differences in willingness to consider joint replacement [12]. Our study did not support this specific finding of the VA study. Our study did link greater expectations with increased willingness to consider TKR in AAs and WHs with OA separately, however.

We also found that minimal levels of religiosity determined willingness among AAs to undergo TKR. Indeed, many studies have shown that prayer is a common self-care treatment used by AAs [13, 38, 39]. Perceiving prayer as helpful also accounted for differences between AA and WH veterans in their attitudes toward TKR [13]. In contrast, in the Texas study strength in religious belief was unrelated to patient preference for TKR [20]. However, this latter study used a single-item rather than a four-item, ordinal scale to measure the level of religiosity, and multi-item scales tend to outperform single items in terms of predictive validity [40].

Trust in physicians was relevant in AA OA patients’ treatment preferences for TKR. In parallel, trust in healthcare was important in WH OA patients’ preferences. The role of patient trust in providers and the healthcare system in determining preferences has been observed in studies of patients with OA and other diseases [20, 41]. Moreover, mistrust of healthcare organizations and health professionals had been associated with less utilization of health services in other patient populations [42, 43].

The implications of our findings are highly relevant. Decision aids and other educational tools may be designed to educate patients about the benefits and risks of the procedure, and expectations for during and after the procedure. Albeit limited, a few patient-centered educational programs to address such matters have already been developed [44]. Educational strategies and training targeted towards healthcare professionals may also be developed to improve patient trust in physicians and the healthcare system. As a consequence, we may improve OA patients’ preference towards more effective and evidence-based treatments, including TKR. Eventually, we may be able to personalize intervention programs and reduce racial disparities in the utilization of TKR among OA patients.

There are limitations to consider in interpreting the study results. First, the cross-sectional design of this study limits our ability to infer a causal relationship. For instance, we cannot determine whether unwillingness to undergo TKR among WHs was due to prior surgical referral or whether not receiving a surgical referral for TKR was due to unwillingness to have the procedure done. The latter is more likely than the former, as patient preferences for treatments for OA were likely to have been established during the early stages of the disease. Second, we did not determine whether patients were anticipating TKR in the near future. Participants who were in this situation might have been more willing to undergo surgery than patients for whom TKR was a mere hypothetical option. This question was excluded from the survey to minimize patient burden. Third, we included only AAs and WHs, and our findings may not be generalizable to patients from other racial groups. Evaluation of the treatment preferences among other racial and ethnic minorities should be conducted in the future.

We have identified relatively modifiable factors that determine patient willingness to consider joint replacement, by patient race. Expectations of joint replacement surgical outcomes were associated with preferences for TKR in both races. Adequate understanding of the procedure, minimal perceptions of pain and difficulties after surgery, and higher trust in physicians determined willingness to undergo joint replacement among AAs. Among WHs, trust in the healthcare system and having a surgical discussion with a physician also determined willingness. The findings of this study may lead to the development of highly specific programs that could reduce or possibly eliminate racial and ethnic disparities in the utilization of joint replacement surgery and other clinical outcomes of patients with OA. Hence, we may be able to enhance the quality of care of all patients with this debilitating disease.