Association of income and prescription drug coverage with generic medication use among older adults with hypertension

Objective: To determine whether low-income seniors and those without prescription drug coverage are more likely to use generic cardiovascular drugs than more affluent and better insured adults. Study Design: Cross-sectional analysis. Methods: We used data from the 2001 Medicare Current Beneficiary Survey. Analyses included noninstitutionalized survey respondents over age 65 years with hypertension who used >= 1 multisource cardiovascular drugs (N = 1710). We examined the association of income and prescription coverage with use of generic versions of multisource drugs from 5 classes: angiotensin-converting enzyme (ACE) inhibitors, beta-adrenergic receptor antagonists (beta-blockers), calcium channel blockers, alpha-adrenergic receptor antagonists (alpha-blockers), and thiazide diuretics. Results: Rates of generic medication use were 88.5% (beta-blockers); 92.8% (thiazides); 58.7% (calcium channel blockers); 60.7% (ACE inhibitors); and 52.6% (alpha-blockers). In multivariate anaysis of generic medication use aggregated across the 5 drug classes, individuals with incomes below 200% of the federal poverty level were modestly more likely to use generic medications compared with seniors with incomes above 300% the poverty level. Seniors who lacked prescription coverage were more likely to use generics than those who had employer-sponsored coverage, although the association was of marginal statistical significance (relative risk = 1.29, 95% confidence interval = 1.00, 1.60). Conclusion: Seniors with low incomes or no prescription coverage were only somewhat more likely to use generic cardiovascular drugs than more affluent and insured seniors. These findings suggest that physicians and policy makers may be missing opportunities to reduce costs for Medicare and its economically disadvantaged beneficiaries.