Exploring rates of PCSK9 inhibitor persistence and reasons for treatment non-persistence in an integrated specialty pharmacy model

Abstract

Nearly 40% of patients do not continue proprotein convertase subtilisin/kexin type 9 inhibitor (PCSK9i) therapy after 6 months, despite their ability to lower low-density lipoprotein cholesterol (LDL-C) and risk of cardiovascular events. Limited work has assessed persistence to PCSK9i therapy in an integrated specialty pharmacy model. To assess rates of persistence to PCSK9i therapy and report reasons for non-persistence in patients serviced within an integrated specialty pharmacy. We conducted a single-center, retrospective review of patients prescribed a PCSK9i at an academic health system between September 2015 and August 2018. Persistence was calculated as a binary measure (yes/no) of whether the patient was still receiving PCSK9i therapy at 3-, 12-, and 24-months; frequency distributions described reasons for non-persistence and descriptive statistics described the change in LDL-C from baseline to 24 months. 477 patients met inclusion criteria, 53% were male with median age of 63 years [IQR 56-70]. Median LDL-C at baseline was 157mg/dL and 86% had an atherosclerotic cardiovascular disease indication. Persistence at 3-, 12-, and 24-months was 94%, 80%, and 68%, respectively. Of the 262 patients persistent on PCSK9i therapy at 24 months with LDL-C values available, median LDL-C was 65 mg/dL. The most common reasons for non-persistence at 24 months included medication adverse effects (54%) and loss to follow-up (17%). High rates of persistence to PCSK9i were seen in patients receiving care within an integrated specialty pharmacy model compared with rates in previous studies, suggesting specialty pharmacists may play a role in mitigating many common reasons for PCSK9i non-persistence.