Purpose: In the general population, lack of adherence to statin therapy remains a widespread phenomenon and an important matter of concern both in terms of cost-effectiveness and risk-benefit profile. This study aimed to evaluate the occurrence of cardiovascular events in Italian statin recipients, focussing on the relationship between degree of adherence to therapy and occurrence of events in a 3-year follow-up.
Methods: Our cohort consisted of all patients from Emilia Romagna (4,027,275 inhabitants) who received statin prescriptions in January-February 2005 and who were followed for up to 36 months for cardiovascular hospital admission (i.e. coronary disease, cerebrovascular accidents, peripheral arthropathy), adherence to statin treatment (proportion of days covered: ≥ 80%) and use of other cardiovascular drugs. The relationship between adherence and cardiovascular events was analysed by multivariate logistic regression; age, sex, other cardiovascular drugs and previous events were covariates of the model.
Results: Patients non-adherent to a statin regimen over the 3-year period (76% of the cohort) had higher odds of events, irrespective of risk factors, by more than 40% when compared with adherent patients. Odds of events were in particular: strongly non-adherent, adjOR=1.19 (CI95% 1.15-1.23), slightly non-adherent, adjOR =1.25 (1.21-1.30), highly variable in the amount of statins received, adjOR=1.69 (1.62-1.77).
Conclusions: This study shows the key role of adherence to statins in cardiovascular prevention at any level of risk. Appropriateness of statin use needs not only careful selection of patients to be treated, but also cooperation between patient and physician to ensure continued drug use whenever treatment is appropriate.