Objectives: To determine statin adherence rates in patients enrolled in a cardiovascular secondary disease prevention program and to evaluate the impact of adherence on subsequent clinical events.
Methods: Patients who had an incident cardiac event between January 1, 2000, and December 31, 2005, and began statin therapy within 90 days of that event were identified and followed until death, a recurrent nonfatal cardiac event, or December 31, 2006. Analysis was conducted in 2007 and 2008. Adherence was calculated using proportion of days covered (PDC), which was dichotomized into overall PDC >80% and PDC <or=80%. Cox proportional hazards models were used to assess the association between PDC and time to death from any cause and/or recurrent nonfatal events.
Results: There were 2201 patients in the study. The overall PDC was 75.4% over 3 years. The risk of any-cause death was lower in patients with a PDC >80% compared with those with a PDC <or=80% (adjusted hazard ratio [HR] = 0.44; 95% confidence interval [CI] = 0.30, 0.64). There was no difference between groups in nonfatal cardiac events. Patients with a PDC >80% had decreased risk of the combined outcome of death or nonfatal recurrent cardiac event compared with those with a PDC <or=80% (HR = 0.75; 95% CI = 0.61, 0.93).
Conclusion: Although our adherence rates were higher than those previously reported in the literature, statin nonadherence still is associated with higher mortality, demonstrating the need to continue to improve statin adherence in this population.