Adherence With Statin Therapy in Elderly Patients With and Without Acute Coronary Syndromes

To compare 2-year adherence following statin initiation in 3 cohorts of patients: those with recent acute coronary syndrome (ACS), those with chronic coronary artery disease (CAD), and those without coronary disease (primary prevention). DESIGN AND SETTING: Cohort study using linked population-based administrative data from Ontario. PATIENTS: All patients aged 66 years or older who received at least 1 statin prescription between January 1994 and December 1998 and who did not have a statin prescription in the prior year were followed up for 2 years from their first statin prescription. There were 22,379 patients in the ACS, 36,106 in the chronic CAD, and 85,020 in the primary prevention cohorts. MAIN OUTCOME MEASURES: Adherence to statins, defined as a statin being dispensed at least every 120 days after the index prescription for 2 years.

Two-year adherence rates in the cohorts were only 40.1% for ACS, 36.1% for chronic CAD, and 25.4% for primary prevention. Relative to the ACS cohort, nonadherence was more likely among patients receiving statins in the chronic CAD (relative risk [RR], 1.14; 95% CI, 1.11-1.16) and primary prevention cohorts (RR, 1.92; 95% CI, 1.87-1.96).