Associated with a significant reduction in cerebrovascular events in secondary prevention, only atorvastatin resulted in significantly fewer events than controls. On the contrary, simvastatin and lovastatin were prescribed mainly for primary prevention. Nevertheless, there are no recommendations supporting the preferential use of a particular statin for primary or secondary prevention. Despite several randomized controlled clinical trials have shown that only a continuous treatment with statins is effective in achieving a reduction of cardiovascular morbidity and mortality, as pointed out by the Delibera Regionale, we found that less than 50% of patients who newly initiated a statin were still adherent to the treatment after six months of follow-up, with a further reduction to 26% after 4-year of follow-up. This data are consistent with previous investigations that suggested a poor level of Temozolomide Autophagy inhibitor adherence to statin treatment and, consecutively, a reduction of long-term effectiveness. Looking at the predictive factors of non-adherence after 4-years from the start of the statin therapy, the probability to be non-adherent was 26% higher for women than for men, suggesting that women have lower perceived risk of disease. Moreover, patients on primary prevention had 64% higher probability to be non-adherent than those on secondary. In line with previous studies performed in similar Italian settings, our data suggested that starting a statin for secondary prevention seems to be predictive factor for higher long-term adherence. This could be explained by the hypothesis that, while the healthiest people has a minor perception of the risk, less-healthy people are strongly motivated, by GPs or by themselves, to continue the therapy to achieve the therapeutic goal. In addition, the use of simvastatin, pravastatin, fluvastatin or lovastatin as first line therapy seems to predict higher probability to be non-adherent as compared to atorvastatin. There is no previous evidence to explain these results; the higher use of atorvastatin in secondary prevention could partially explain this evidence. Moreover, since the discontinuation of treatment, as defined for MPR calculation, does not consider if a patient switched across statins, we cannot exclude that people starting with simvastatin, pravastatin, fluvastatin or lovastatin could have changed the type of statin as consequence of the occurrence of adverse effects or as lack of efficacy. To date, lack of efficacy and drug therapeutic failure are included within the wider definition of adverse drug event given by the World Health Organisation and it is proposed as a peculiar type of adverse drug reaction designated as “Failure”. However, since healthcare providers may have a crucial impact on patients’ adherence to medication, the identification of these patient-related predictors for non-adherence could be useful to increase the compliance. This drug-utilization study aimed to measure the use of statin in a general practice of southern Italy.