Recent trends in cost-related medication nonadherence among stroke survivors in the United States

Abstract

Objective: Recent economic and health policy changes may have affected the ability of chronically ill patients to afford their medications. We assessed changes in cost-related nonadherence to medication (CRN) before and after the implementation of Medicare Part D in 2006.

Methods: We used data from the National Health Interview Survey, an annual, population-based survey of community-dwelling, noninstitutionalized US adults, to estimate CRN in 8,673 stroke survivors aged 45 years or older, representing 4.8 million survivors, for the years 1999 to 2010. The main outcome measure was CRN, defined as self-reported inability to afford prescribed medication within the past 12 months.

Results: During the period 1999 to 2010, 11.4% of stroke survivors, approximately 543,000 individuals, reported CRN. From 1999 to 2010, CRN more than doubled among stroke survivors aged 45 to 64 years (from 12.7 to 26.5%; ptrend = 0.01). CRN remained stable among those aged 65 years or older (from 3.8 to 7.0%; ptrend = 0.21). From 1999-2005 to 2006-2010, CRN among uninsured stroke survivors aged 45 to 64 years increased from 43.1 to 57.1% (p = 0.03). Among stroke survivors aged 65 years or older with Medicare coverage, CRN was higher among Medicare Part D participants than those without the drug benefit (7.9 vs 4.8%; p = 0.02). After adjustment for sociodemographic and clinical factors, CRN was similar among Medicare Part D enrollees and nonenrollees.

Interpretation: From 1999 to 2010, CRN increased significantly among stroke survivors younger than 65 years, particularly among those without health insurance. There was no evidence that Medicare Part D decreased CRN among stroke survivors with Medicare.

Figure 1. Percentage of US Stroke Survivors Who Did Not Get Needed Prescription Drugs Because of Cost, by Age Group and Year, Before and After Adjustment: National Health Interview Survey, 1999–2010

Adjusted for sex, race, Hispanic ethnicity, education, insurance, family income to poverty level ratio, health status, modified Charlson co-morbidity score, and functional disability. P=0.01 for trend over time (χ² test) from unadjusted model for age group 45–64 years. P=0.21 for trend over time (χ² test) from unadjusted model for age group 65+ years. P=0.08 for trend over time (χ² test) from fully adjusted model for age group 45–64 years. P=0.90 for trend over time (χ² test) from fully adjusted model for age group 65+ years. Analyses accounted for the complex sampling design and used proper variance estimations to produce results that were weighted to reflect national population estimates.