Effects of health insurance on racial disparity in osteoporosis medication adherence

Objective: To explore whether racial disparity in osteoporosis drug therapy maintenance varies by health insurance coverage status. Design: Longitudinal observation study. Setting: Cleveland Clinic Health System (Cleveland, OH) from January 2006 to December 2009. Patients: 3,901 black and white female Medicare beneficiaries starting osteoporosis drug therapy. Intervention: Analysis of the health system's integrated electronic medical records. Main outcome measures: Drug therapy adherence (medication possession ratio ≥80%) for more than 12 of 15 surveillance units and occurrence of extended nonadherence gaps for at least two surveillance units in a row. Results: Among patients with supplementary health insurance (n = 2,278), no difference was observed for drug therapy adherence (P = 0.17) and extended nonadherence gaps (P = 0.53) between black and white participants. When patients did not have supplementary health insurance (n = 1,623), blacks (36% [95% CI 28-47]) were less likely to adhere to drug therapy than whites (47% [38-57]; odds ratio [OR] 0.34 [95% CI 0.09-0.92], P = 0.004). Blacks (25% [19-32]) also were more likely to have an extended nonadherence gap episode than whites (18% [11-26]; OR 2.42 [1.13-3.50], P = 0.03). Conclusion: Similar to previous research on racial disparity in health services, racial disparity in osteoporosis drug therapy maintenance between black and white female older patients existed when supplementary health insurance was not affordable.