Racial disparities in prescription drug use among dually eligible beneficiaries

Health Care Financing Review, Winter, 2003 by Jennifer Schore, Randall Brown, Bridget Lavin

INTRODUCTION

Racial disparities in prescription drug and other health service use, and the relationship of these disparities to differences in health have been explored extensively in the literature (Smedley, Stith, and Nelson, 2003; Mayberry, Mili, and Ofili, 2000; and Mayberry et al., 1999). For example, members of racial minorities are less likely than those of non-minorities to receive appropriate medications for cardiovascular disease and AIDS (U.S. General Accounting Office, 2003). One commonly investigated basis for these disparities is that minority individuals are less likely than non-minority ones to have adequate health insurance. Elderly black Medicare beneficiaries are more than twice as likely as white beneficiaries to not have supplemental insurance and to not fill prescriptions because they cannot afford them (Reed, Hargraves, and Cassil, 2003). Nevertheless, having comparable insurance does not always eliminate disparities. For example, Kuno and Rothbard (2002) found that black Medicaid beneficiaries with schizophrenia were less likely than their white beneficiaries to receive appropriate medications. Likewise, Schneider, Zaslavsky, and Epstein (2002), found that black Medicare managed care enrollees who had suffered heart attacks were less likely than their white beneficiaries to receive beta-blockers. What, then, is the cause of these racial disparities?

Hypotheses abound concerning the causes of racial disparities in health service use even among those with similar insurance coverage and the same medical conditions. These hypotheses include possible differences among racial groups in (1) literacy levels; (2) knowledge about managing chronic conditions (such as monitoring symptoms and adhering to treatment recommendations); (3) expectations of, and trust in the health care system; (4) rapport with or trust in physicians, (5) perceptions about the availability, effectiveness, and risk of medical procedures; (6) tolerance for and attitudes toward pain or functional limitations; and (7) cultural traditions favoring non-traditional or non-invasive care (Chen et al., 2001; DeLew and Weinick, 2000; Gornick, 2000; Katz, 2001). Racial disparities may also be due to provider and system-level problems, including overt or subtle racism; provider beliefs about patient preferences and attitudes; cultural barriers to effective communication, particularly in describing technologically sophisticated procedures and the importance of self-care for chronic conditions; and distance from, and lack of transportation to, care centers (Chen et al., 2001; DeLew and Weinick, 2000; Epstein and Ayanian, 2001; Katz, 2001).

While much research has focused on racial disparities in the receipt of specific medical procedures and the use of preventive and other health care services, relatively little research has examined whether disparities exist in the receipt of prescription medications. However, a few studies have confirmed the existence of racial disparities in utilization of specific prescription medications, especially anti-retrovirals (Nelson, Norris, and Mangione, 2002; Palacio et al., 2002). Receiving a prescription for, and taking, appropriate medications can have enormous effects on health, quality of life, and mortality. Moreover, the broader question remains as to whether historic differences in medical service use by individuals of different races carry over to the use of prescription drugs.

The purpose of this study is to examine racial differences in prescription drug use by Medicare beneficiaries who have comprehensive prescription drug coverage by virtue of also being enrolled in Medicaid. By limiting the population studied to people with the same insurance coverage, and to a group with more homogeneous socioeconomic status than the general Medicare population, and by controlling statistically for the incidence of chronic medical conditions, age, and other characteristics, we are able to examine the magnitude of remaining unexplained differences in prescription drug use.

Among the many potential explanations for racial disparities in health service use nationally, those with particular relevance to differences in use of the Medicaid pharmacy benefit include beneficiary characteristics and health care delivery system characteristics. Beneficiary-specific differences include the incidence of chronic conditions for which prescription medications are considered standard treatment, the propensity to use routine health service providers primarily responsible for prescribing medications (such as physicians), and the propensity to adhere to treatment recommendations (such as renewing and filling prescriptions). Black and white beneficiaries also are distributed among States very differently. This difference could contribute to racial disparities in pharmacy benefit use nationally among dually eligible beneficiaries if the proportion of black beneficiaries in a State were correlated with (say) the stringency of Medicaid eligibility requirements or with how tightly controlled the drug benefit is.