Prevalence and determinants of adherence to statin therapy: a systematic review and meta-analysis
Athanasios Basios, Georgios Markozannes, Evangelia Ntzani, Konstantinos Christopoulos, Christina A Chatzi, Evangelos Liberopoulos, Konstantinos K. Tsilidis, Μαρία Παππά, Evangelos C. Rizos
Abstract
AIM: To estimate the prevalence of good adherence to statin therapy and identify demographic and clinical factors associated with adherence among adults prescribed lipid-lowering therapy (LLT) for atherosclerotic cardiovascular disease (ASCVD) prevention. METHODS: We conducted a systematic search of PubMed and Scopus through May 2025 to identify randomized controlled trials, cohort, nested case-control, and cross-sectional studies evaluating adherence to statin monotherapy. Data were extracted on study design, participant demographics, comorbidities, adherence assessment method and duration, and statin type. A random-effects meta-analysis was performed. Study quality was assessed using the Newcastle-Ottawa Scale, and risk of bias in randomized trials was evaluated with the Cochrane RoB 2 tool. Subgroup and sensitivity analyses examined adherence variations by follow-up duration (<1, 1, >1 year), alternative adherence thresholds, and study quality. "Primary" non-adherence (failure to initiate prescribed therapy) was not reported in any of the included studies. RESULTS: Seventy-six studies encompassing 5,898,141 participants (median follow-up 24 months) were included. The pooled prevalence of good adherence (≥80% medication use) was 62.4% (95% CI: 58.3-66.5%), lower in primary (57.5%) than secondary (64.4%) prevention settings. Factors associated with lower adherence included female sex (RR=0.92), Black race (RR=0.66), smoking (RR=0.94), depression (RR=0.89), and heart failure (RR=0.96). Higher adherence was observed among older adults (RR=1.34), individuals with myocardial infarction (RR=1.28) or hypertension (RR=1.12), those with ≥2 comorbidities (RR=1.25), and patients with polypharmacy (RR=1.32). Subgroup and sensitivity analyses yielded consistent results. CONCLUSIONS: Adherence to statin therapy remains suboptimal and is significantly influenced by demographic and clinical factors. Targeted strategies are needed to improve adherence, particularly in high-risk groups.