Adherence to statin therapy in women and men: a population-based cohort study from routine care data

Aim To assess adherence to statin therapy in women and men in Dutch routine care data.Methods Data on statin dispensing was extracted from the PHARMO Data Network in the Netherlands between 2011 and 2020. We assessed primary non-adherence, non-compliance and discontinuation of statin therapy in a population-based cohort of new statin users aged >40 years and assessed sex differences. We evaluated the association of non-compliance with cardiovascular hospitalisations and mortality with Cox proportional hazard models weighted with inverse probability weights.Results We identified 68 707 new users of statin therapy (46% women) with a median age of 65 years (Q1–Q3: 57–72). In total, 9% of women and 8% of men were primary non-adherent, with women being 8% (95% CI 4 to 12) more likely to be primary non-adherent in the first year after initiating statins compared with men. The mean proportion of days covered in this first year after initiation was 81% for women and 83% for men; the adjusted women-to-men risk ratio for non-compliance was 1.06 (95% CI 1.03 to 1.08). The cumulative incidence of discontinuation at 1 year was 23% in women and 20% in men, with women being 13% (95% CI 10 to 15) more likely to discontinue statin therapy compared with men. Non-compliance to statin therapy was associated with a 17% higher risk of cardiovascular hospitalisations and mortality in women (95% CI 10 to 23) and 14% higher risk in men (95% CI 8 to 20) (ratio of HRs: 1.02 (95% 0.95 to 1.11)).Conclusion Women were less likely than men to be adherent to statin therapy, though the differences were marginal in absolute terms. Non-adherence was associated with a higher risk of cardiovascular hospitalisations and mortality.