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.