Impact of adherence to statins on chronic heart failure in primary prevention

AIMS Statins are effective in the prevention of an atherosclerotic event, e.g. coronary artery disease and cerebrovascular disease. Patients at high risk of cardiovascular disease (CVD), such as chronic heart failure (CHF), might benefit from the effects of statin therapy. However, one question that has not yet been answered and that may clarify the role of statins in CHF is whether statins prevent the development of CHF in patients with a low risk of CVD. Our aim was to evaluate the impact of adherence to statins on the incidence of CHF. METHODS A cohort of 111 481 patients was reconstructed using the Regie de l'Assurance Maladie du Quebec databases. Patients were eligible if they were between 45 and 85 years old, without CVD, and newly treated with statins between 1999 and 2004. A nested case-control design was used to study CHF. Every case of CHF was matched for age and duration of follow-up in up to 15 randomly selected controls. The adherence level was measured by calculating the medication possession ratio. Rate ratios (RR) of CHF were estimated by conditional logistic regression adjusting for several covariables. RESULTS The mean patient age was 63 years, 49% had hypertension, 21% had diabetes and 41% were male. A high level of adherence to statins was associated with a reduction of CHF (RR 0.81; 0.71, 0.91). The risks associated with CHF were the development of CVD during follow-up, being a social-aid recipient, and suffering from hypertension, diabetes mellitus, or having a higher chronic disease score. CONCLUSION Our study indicates that better adherence to statins is associated with a reduced risk of CHF.