Social disparities in the use of prescription medications among older adults in the U.S: A population-based approach

Background: Social disparities in the use of prescription medication may be an important, yet overlooked, contributor to persistent social disparities in health. The majority of existing data sources for which prescription medication use measures are derived, however, are not population-based and therefore disproportionately exclude data on the most socially disadvantaged populations (including racial/ethnic minorities) that may experience limited access to prescription medications. Thus, information on social disparities in the use of prescription medications is incomplete. This information is particularly important for the developTitlement of pharmaceutical policies intended to improve access to prescribed medications in these populations.

Objectives: This study will use population-based medication data to describe patterns in the use of prescription medications by socioeconomic status and race/ethnicity, and  identify social and health care factors associated with racial/ethnic disparities in the use of prescription medications.

Design, Setting and Study Population: In-home interviews were administered between June 2005 and March 2006 to 3005 community-residing individuals, ages 57–85 years, drawn from a cross-sectional, population-based sample of the United States. Prescription medication use was defined as the use of at least 1 prescription medication. Multistage, multivariable logistic regression models were developed to examine the social and health care factors associated with racial/ethnic disparities in the use of prescription medications.

Outcome measures: Prevalence of prescription medication use by socioeconomic status and race/ethnicity.

Results: Individuals living in poverty were 60% less likely to use prescription medications in comparison to their non-poor counterparts (OR 0.40 (CI 0.24, 0.68). After adjusting for differences in age and health status, Black and Hispanic minorities were 40% and 45% less likely, respectively, to use prescription medications in comparison to their White counterparts. Racial/ethnic differences in the use of prescription medications are reduced after the introduction of factors representing poverty and access to primary care. In contrast to previous studies, differences in insurance status and education did not explain racial/ethnic disparities in the use of prescription medications.

Conclusions: This study provides population-based evidence of social disparities in the use of prescription medications among older adults in the United States. These findings suggest that policy efforts to improve access to prescription medications in minority communities need to address factors beyond insurance-centered affordability, including barriers associated with poverty (e.g. geographic access to pharmacies) and access to primary health care. In addition, social disparities in access to prescription medications should be incorporated into models examining social determinants of health in the U.S. and globally.