Impact of medication nonadherence on hospitalizations and mortality in heart failure

Background: Limited literature exists on the association between medication adherence and outcomes among patients with heart failure. Methods and Results: We conducted a retrospective longitudinal cohort study of 557 patients with heart failure with reduced ejection fraction (HFrEF) (defined by EF <50%) in a large health maintenance organization. We used multivariable Cox proportional hazards models to assess the relationship between adherence (with angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, β-blockers, and aldosterone antagonists) and the primary outcome of all-cause mortality plus cardiovascular hospitalizations. Mean follow-up time was 1.1 years. Nonadherence (defined as <80% adherence) was associated with a statistically significant increase in the primary outcome in the cohort overall (hazard ratio 2.07, 95% confidence interval 1.62-2.64; P < .0001). This association remained significant when all 3 classes of heart failure medications and the components of the composite end point were considered separately and when the adherence threshold was varied to 70% or 90%. Conclusions: Medication nonadherence was associated with an increased risk of all-cause mortality and cardiovascular hospitalizations in a community heart failure population. Further research is needed to define systems of care that optimize adherence among patients with heart failure.