(Nelson et al., 2002) also complicate the picture. In addition, blacks and Hispanics are reported to distrust health care providers and expect discriminatory treatment more often than whites (LaVeist et al., 2000; Lillie-Blanton et al., 2000), but whether this affects their acceptance of recommended treatments or compliance with prescribed regimens has not been clearly demonstrated.
Improvements in health care by themselves are unlikely to either eliminate social inequalities in health or achieve optimal levels of population health (House and Williams, 2000; Kaplan et al., 2000).
Some evidence indicates that medical care explains only 10 percent of variation in adult mortality (U.S. Department of Health, Education, and Welfare, 1979), which has led to the widely held view that medical care makes a limited contribution to population differences in health status (Adler et al., 1993). However, medical care may have a greater effect on the health status of vulnerable populations, such as racial and ethnic minorities and low-status groups among older adults, than on the population in general (Williams, 1990). What this effect could be, what differences actually exist beyond those now documented, how they interact with multiple vulnerabilities in the older population, and how health care should be properly structured to address differences are all issues that require attention.
Research Need 14: Identify differences in health care—access, use, and quality—for racial and ethnic minority populations other than blacks.
To date, most research on differences in care has focused on blacks and whites, partly reflecting the absence in the Medicare file of high-quality ethnic identifiers for other groups. The few studies that have identified differences in quality and intensity of care for other groups leave the extent of the differences faced by Hispanics, American Indians and Alaska Natives, and Asians unclear (Institute of Medicine, 2002).
Research Need 15: Determine the reasons for differences in health care quality, focusing on the contributions of geographic variation, characteristics of health care institutions, provider behavior and stereotypes, and patient adherence to recommendations for care.
Multiple factors are almost certainly involved, as they are with differences in health outcomes, and need to be assessed against each other. Medical care may vary because of the health needs of different groups, or the types of care they seek, prefer, or can afford, or because of insurance coverage, provider behavior, or the policies and procedures of hospitals and