Risk factors for drug-treated major adverse cardio-cerebrovascular events in patients on primary preventive statin therapy: A retrospective cohort study

We aim to identify risk factors of major adverse cardio-cerebrovascular events (MACCE) using a proxy of drug treatment for a MACCE after the start of statin therapy in the primary cardiovascular prevention group, taking drug dose, persistency and adherence into account. We conducted a retrospective inception cohort study using data from the University of Groningen prescription database IADB.nl, covering patients in the Northern part of the Netherlands. We identified adult starters on primary preventive statin therapy as patients without any statin or cardiovascular drug prescription in the two years before the first statin dispensing and used a weighted Cox proportional hazard model to estimate hazard ratios (HR) with their 95 % confidence intervals (95 %CI). Among 39,487 primary preventive statin starters, 23% received drug treatment for a MACCE within a median follow-up period of four years. Increasing age, male gender and presence of diabetes drug treatment were significantly associated with the outcome (HR: 1.03; 95 %CI: 1.02-1.04; HR: 1.27; 95 %CI: 1.12-1.44 and HR: 1.39; 95 %CI: 1.24-1.56, respectively). If patients remained statin therapy persistent, adherence was no longer associated with drug treatment for a MACCE. In 23 % of the statin therapy initiators, incident drug treatment for a MACCE occurred with a median of four years. To reduce event rates in this group, older patients, males and diabetes patients should be closely monitored. Non-adherence in the early stage of treatment should be avoided to prevent non-persistence.