2010 Articles

Predictors of nonadherence to statins: a systematic review and meta-analysis

Mann, Devin M.; Woodward, Mark; Muntner, Paul; Falzon, Louise; Kronish, Ian M.

Background—Non-adherence to statins limits the benefits of this common medication. Individual studies assessing predictors of non-adherence have produced inconsistent results.

Objective—The objective of this systematic review and meta-analysis was to identify reliable predictors of non-adherence to statins.

Methods—Multiple databases, including Medline, EMBASE and Psychinfo, were searched to identify studies that evaluated predictors of non-adherence to statins. Studies were selected using a priori defined criteria, and each study was reviewed by 2 authors who abstracted data on study characteristics and outcomes. Relative risks were then pooled using an inverse-variance weighted random-effects model.

Results—Twenty-two cohort studies met inclusion criteria. Age had a U-shaped association with adherence; the oldest (≥ 70 years) and youngest (< 50 years) had lower adherence than the middleaged (50–69 years). Women and those with lower incomes were more likely to be non-adherent than men [odds of non-adherence 1.07 (95% CI 1.04 – 1.11)] and those with higher income [odds of non-adherence 1.18 (95% CI 1.10 – 1.28)], respectively. A history of cardiovascular disease predicted better adherence to statins [odds of non-adherence 0.68 (95% CI 0.66–0.78)]. Similarly, a diagnosis of hypertension or diabetes was associated with better adherence. Although there were too few studies for quantitative pooling, increased lipid testing and lower out-of-pocket costs appeared to be associated with better adherence. There was substantial (I2 range 68.7–96.3%) heterogeneity between studies across factors.

Conclusion—Several socio-demographic, medical, and healthcare utilization characteristics are associated with statin non-adherence. These factors may be useful guides for targeting statin adherence interventions.