Discussion

We conducted a review of publicly available studies addressing four separate hypotheses linking increased racial, ethnic, and socioeconomic diversity among health professionals to improved public health. We found a large and consistent body of evidence suggesting that minority health professionals, particularly physicians, disproportionately serve minority and other medically underserved populations. Data generally supported the notion that minority patients receive better interpersonal care from practitioners of their own race or ethnicity, particularly in primary care and mental health settings. Patient-practitioner language concordance similarly was associated with better interpersonal care, greater medical comprehension, and greater likelihood of keeping follow-up appointments, particularly in mental health care. For two of our hypotheses—that greater health professions diversity leads to greater trust in health care and greater advocacy for disadvantaged populations—empirical evidence was scant or lacking.

Collectively, the studies in our review suggest several mechanisms by which increasing numbers of minority and socioeconomically disadvantaged health professionals in the United States. might lead to improved health outcomes. First, minority physicians, and to a lesser degree those from socioeconomically disadvantaged backgrounds, serve as a usual source of care for many of the nation’s underserved populations, including those who are uninsured or underinsured. Studies have established that having access to a usual source of care improves health outcomes. (15-17) To the extent that future minority health professionals follow this pattern of disproportionately caring for the underserved, increasing minority representation among health professionals should increase access to health care for underserved groups and thereby improve population health.

Second, increasing health professions diversity would afford minority patients, particularly those from groups underrepresented in the health professions, greater opportunity to see practitioners of their own racial or ethnic background. Increased diversity would thereby improve the quality of interpersonal care that minority patients receive, and potentially increase their likelihood of receiving and accepting appropriate medical care, which would in turn lead to improved health. One study in our review supported this contention by demonstrating that African-American patients received life-prolonging medications for HIV/AIDS in a more timely manner from African-American as opposed to White physicians.

Finally, increasing the presence of underrepresented Latino and Asian health professionals in particular might afford more limited English-proficient patients the opportunity to see practitioners that speak their native language. The observation of higher-quality care in language concordant relationships—most likely a result of effective communication and possibly of cultural congruence—suggests that greater linguistic diversity among health professionals will lead to improved health outcomes and greater patient safety.(75-77) This is particularly relevant in the current context of limited funding for and use of medical interpreter services.(78)

Some caveats to these arguments for health professions diversity warrant mention. First, considering minority practitioner service patterns as the primary rationale for diversity programs may lead to the problematic expectation that minority health professionals should all serve underserved patient populations. It is important to remember that our review supports the notion that increasing workforce diversity will lead to greater access to care through the choices of minority practitioners (to serve underserved populations) and minority patients (to seek care from minority practitioners). We would consider it unethical to require practitioners to serve specific populations based on their race, ethnicity, or socioeconomic background.

Second, we caution against the conclusion that, because race concordance is associated with higher quality care, patients should always be paired with practitioners of their own race. Although studies in our review suggested that interpersonal care was on balance better in race concordant patient-practitioner relationships, and that patients tended to prefer practitioners of their own race, these findings did not apply to all patients and practitioners. In most studies, the majority of patients had no preference regarding practitioner race and were very satisfied with the care they received from race discordant providers. The association between race concordance and interpersonal quality indicates that greater diversity might improve overall quality of care by affording those who do have a preference, and who do experience better care in race concordant relationship, greater opportunity to have such relationships.

Finally, it is important to note that we were not able to determine the separate effects of language concordance alone vs. language plus ethnic concordance. One path to greater patient-practitioner language concordance for limited English-proficient patients is to increase racial and ethnic diversity in the health professions. Another path is to train non-minority health professionals to speak non-English languages. This latter strategy could enhance language concordance but would lack the potential benefit of combined language and ethnic concordance. We were not able to determine whether this combined concordance was more beneficial than language concordance alone. Thus, while our review suggested a potential benefit from increasing language concordance in patient-practitioner encounters, it did not establish whether achieving this benefit is best accomplished by training more minority health professionals or by training existing and future health professionals to speak non-English languages.

Study Limitations
There were several limitations to our review. Our search strategies may not have captured all relevant studies. We took several measures to ensure a comprehensive search, including reviewing reference lists and Web sites and consulting with experts. It is possible, though, that important studies were missed. We only searched for publicly available studies. Some studies relevant to our review may have been conducted by private institutions that did not disseminate their findings to the general public. It is also possible that our review was affected by publication bias, as some authors may have selectively chosen not to publish results either supporting or refuting the hypotheses we addressed.

Recommendations for Future Research
Our review revealed several gaps in the evidence base related to health professions diversity that we believe are important areas for future research. Notably, nearly all the studies we found related to service patterns examined physician practices. More studies are needed to determine whether the service patterns of other professionals who serve as many patients’ usual source of health care (e.g., nurse practitioners, physician assistants) vary according to race, ethnicity, or socioeconomic background. Likewise, studies of patient-practitioner racial and ethnic concordance were limited primarily to physicians and mental health practitioners. It would be useful to know about the impact of concordance between patients and other health professionals, particularly nurses, who interact closely with patients—in hospitals, long-term care facilities, doctors’ offices, and even in patients’ homes—and whose interpersonal interactions are therefore likely to substantially influence patients’ experiences.

Future studies of racial and ethnic concordance should look beyond the quality of interpersonal care (e.g., patient satisfaction) and begin to study the impact of concordance on more objective measures of quality, including process measures (e.g., receipt of influenza vaccination among elderly and chronically ill patients) and health outcomes (e.g., glycohemoglobin level among patients with diabetes). In designing and conducting such studies, researchers should choose measures that are likely to be strongly influenced by interpersonal interactions between health care providers and patients, i.e., those for which a link with patient-practitioner concordance makes sense. Researchers should also be mindful in conducting these studies that, relative to measures of interpersonal quality, process and outcome measures are influenced by numerous factors other than the patient-practitioner interaction. Studies examining process and outcome measures must therefore take these potentially confounding factors into account and be adequately powered to detect the influence of concordance amidst the influence of many other variables. Using data from large clinical and administrative databases is one way to harvest the kind of power that may be needed for such studies, but it will require that the databases contain, or at least can be linked to, data on patient and practitioner race. Organizations such as Aetna, who are now collecting these data routinely,(79) may serve as a resource and a model for other health care organizations interested in health professions diversity.

Studies of language concordance to date have not adequately examined the relative contributions of language concordance alone vs. combined language and ethnic concordance. It is not clear, therefore, whether the observed effects in these studies are attributable solely to language concordance or are in part explained by the ethnic (and perhaps cultural) concordance that are often present in language concordant encounters. The policy implications of language concordance studies depend, at least in part, on the relative contributions of these separate effects. If common language accounts for all of the benefits of language concordance, then interventions to enhance practitioners’ non-English skills (e.g., Spanish language courses) might suffice to improve care for patients with limited English proficiency. If ethnic concordance were influential, policies to increase ethnic diversity among health professionals would likely be needed. Therefore researchers should compare the quality of care in encounters and relationships in at least three categories: concordant language/ethnicity, concordant language/discordant ethnicity, and discordant language/ethnicity. In conducting such studies, researchers should pay attention to and measure non-English fluency among practitioners and English fluency among patients, since language concordance is best conceived as a continuous (or ordinal), rather than dichotomous variable.

Studies of the effect of institutional diversity on patients’ trust in health care and propensity to use health care services are lacking. Research in this area could start by measuring trust, perceived access, satisfaction, and likelihood of using services among patients receiving care at (or with the option to receive care at) health care facilities with differing levels of staff diversity. It is important that such studies account for other differences across institutions that might affect patients’ attitudes and choices. Because minority professionals are more likely to practice in underserved communities, the facilities they work in may be less well reimbursed than facilities staffed predominantly by non-minority professionals. Patients’ attitudes toward certain health care facilities may appear negative, despite their diversity, if those institutions have long waiting times, inadequate resources, or even an unattractive physical appearance.

It is also important in studies of the effects of institutional diversity to measure both structural diversity—the proportion of a facility’s staff from different racial/ethnic groups—and interactional diversity—the degree to which patients interact with staff from different racial or ethnic groups. Structural diversity alone may be important, in that patients may trust an institution more, simply because it has a diverse workforce. But it is more likely that the influence of diversity on patients’ trust and use of services, if such an influence exists, will be mediated by their experiences and interactions with individuals within that institution.

Finally, research is needed to test the proposed hypothesis that a greater presence of professionals from minority and socioeconomically disadvantaged backgrounds in the health care workforce will lead to greater leadership and advocacy, and ultimately better access and quality of care for disadvantaged populations. This research could begin with a simple survey assessing the priorities of health care leaders from different racial, ethnic, and socioeconomic backgrounds. Another study might examine the research portfolios of researchers from different backgrounds. Do minority researchers spend relatively more effort on issues important to minority and other disadvantaged patient populations? This could be done, for instance, by examining the portfolios of NIH-funded researchers. The National Academy of Sciences (NAS) conducts periodic evaluations of NIH programs aimed at recruiting minority scientists and fostering their careers.(80) The NAS could incorporate into these evaluations an investigation of the research focus and populations studied among beneficiaries of these programs, as compared to other researchers.