The effects of adherence and persistence on clinical outcomes in patients treated with statins: A systematic review

BackgroundIn clinical practice, medication adherence and persistence are important for disease management and can significantly improve outcomes and enhance the quality of patient care. Quantifying the relationship between medication adherence/persistence and clinical outcomes with statins can serve as an important therapeutic model and complement our understanding of the critical relationship between medication use and improved patient care.Methods and ResultsA PubMed search was conducted for literature published between 1999 and 2009 using the terms adherence, compliance, HMG CoA, nonadherence, noncompliance, persistency, persistence, and statin. Data on the direct relationship between adherence or persistence to statin monotherapy and clinical outcomes were extracted. A total of 19 articles met the inclusion criteria, including the clinical impact of adherence (n = 15) and persistence (n = 4). High levels of adherence were associated with reductions in adverse clinical outcomes, including all-cause mortality and fatal and nonfatal cardiovascular events; the most consistent benefits were witnessed at adherence levels 80% or greater. In primary prevention cohorts, clinical benefits were seen after 1 year of therapy. Longer durations of treatment were associated with incremental improvements in clinical outcomes as length of therapy increased.ConclusionsHigh levels of adherence and longer durations of persistence with statins are associated with progressively increasing clinical benefits in primary and secondary prevention patient populations at risk for cardiovascular events. Efforts to improve adherence and persistence are warranted.