Persistence and determinants of statin therapy among middle-aged patients free of cardiovascular disease

Aim. Statins have been shown to significantly reduce morbidity and mortality both in patients with coronary artery disease and in those with dyslipidemia when they are taken regularly. Middle-aged patients have the highest level of forecasting benefit, and little is known about the persistence rate of these therapies in a real-life setting.Objective. To evaluate the persistence rate of middle-aged patients initiating statin therapy as well as its relation to patients' demographic and clinical characteristics.Methods. A cohort of 25,733 patients was reconstructed from prescription data recorded in the Regie de l'assurance maladie du Quebec administrative database. All patients aged 50-64 years old who received at least one statin prescription between January 1, 1998 and December 31, 2000 for a new intention of treatment for dyslipidemia were included in the cohort and followed up until June 30, 2001. The date of the first prescription of statin was defined as the index date. The cumulative persistence rate was estimated using a Kaplan-Meier analysis. Cox regression models were used to estimate the rate ratio of ceasing statins after adjustment. Results. Mean age of patients initiating statin agents was 58 years; 39%were male, 24% received social assistance, 19% had diabetes, 30% had hypertension and 11% had a respiratory disease at cohort entry. Persistence with statin therapy fell to 67% in the first 6 months after treatment and continued to decline over the next 3 years to 39%. At 3 years, persistence varied significantly with statin agents. After controlling for individual patients' demographic and clinical characteristics, we found that patients who were prescribed fluvastatin, lovastatin and atorvastatin had a higher rate of cessation than those on simvastatin and pravastatin. The adjusted rate ratio of ceasing statin agents in patients with other risk factors of cardiovascular disease, such as diabetes (HR: 0.78; 0.75-0.82) or hypertension (HR: 0.72; 0.69-0.74), demonstrated a lower cessation rate. We observed lower persistence in patients who used the greatest number of pharmacies and prescribing physicians.Conclusion. This analysis indicates that barriers to persistence occur early in the therapeutic course. Overall persistence with statins is low, particularly among patients with few other cardiovascular risk factors.