[Low persistence of simvastatin and ezetimibe fixed combination in the lipid lowering therapy]

The high cholesterol level is a well-known modifiable cardiovascular risk factor. Adequate patient adherence is important to decrease the cardiovascular risk.

The aim of the authors was to evaluate the persistence on one-year treatment with the free or fixed combination of simvastatin and ezetimibe and rosuvastatin.

Information from the National Health Insurance Found prescriptions database on pharmacy-claims between October 1, 2012 and September 30, 2013 was analyzed. The authors identified patients who filled prescriptions for fixed or free combinations of simvastatin and ezetimibe and rosuvastatin prescribed for the first time. The subjects have not received antilipemic therapy with similar drugs during the year preceding the study. Using Kaplan-Meier technique, the authors constructed persistence curves with a 95% confidence interval for point estimates calculated on a log scale. Patients who were still persistent at the closing date of the study were considered censored. For the modelling of the curves, the authors used semi-parametric Cox's regression where antihypertensive therapy was the only (categorical) explanatory variable, and the patients taking the fixed combination of simvastatin and ezetimibe were regarded as the reference group.

204,699 patients met the inclusion criteria. During the study period, antilipemic therapy with simvastatin and ezetimibe free combination 10,030 and 7,613 fixed combination of these agents and 187,056 patients with rosuvastatin was started by patients. One-year persistence rate in patients taking simvastatin and ezetimibe as a free combination was 10.97%, whereas it was 24.35% in those on the fixed combination and 30.47% in those on rosuvastatin monotherapy. The hazard ratio of discontinuation of simvastatin and ezetimibe free combination was 1.73 [95% confidence interval: 1.61-1.85], p<0.0001 compared to fixed combination and 0.80 [95% confidence interval: 0.78-0.82], p<0.0001 compared to rosuvastatin. Considering only the 360-day study period, the mean duration of persistence was 107 days in patients on the free, 164 days in those taking the free combination of simvastatin and ezetimibe and 185 days those taking rosuvastatin.

This study demonstrated that one-year persistence of free and fixed combination of simvastatin and ezetimibe was significantly lower compared to rosuvastatin.