Adherence to Lipid-Lowering Treatment by Single-Pill Combination of Statin and Ezetimibe

Introduction: Although several studies have shown that a simplified cardiovascular drug treatment leads to better treatment adherence, limited and conflicting findings have been reported on the separate or single-pill combination of the now recommended association between a statin and ezetimibe. We addressed this issue in a large cohort of patients newly treated with statins to whom ezetimibe was additionally administered, either separately or as a single-pill combination. Methods: A total of 256,012 patients (age 40–80 years) from the Lombardy Region (Italy) newly treated with statins during 2011–2013 were followed until 2018 to identify those to whom ezetimibe was added. The 2881 and 5351 patients who started a two-pill or a single-pill combination, respectively, of statin and ezetimibe were identified and matched for propensity score. Adherence to drug therapy at 1 year was measured as the ratio between the number of days in which the drug was available and the days of follow-up (the proportion of days covered; PDC). Patients who had a PDC > 75% or < 25% were, respectively, defined as highly and poorly adherent to drug therapy. Analysis was extended to the association between adherence and the risk of fatal/non-fatal cardiovascular events. Results: Compared to those prescribed a two-pill combination, those prescribed a single-pill combination had an 87% (75–99%) greater odds of being highly adherent and a 79% (72–84%) lower odds of being poorly adherent to treatment. These advantages were manifest in all strata of age, sex, and clinical profile. The risk of cardiovascular outcomes decreased by 55% in patients with high adherence compared to those with low adherence. Conclusion: Patients who were prescribed a single-pill combination of statin/ezetimibe more frequently exhibit a good adherence and less frequently bad adherence to treatment than those prescribed a two-pill combination of these drugs.