Real-World Outcomes of Proprotein Convertase Subtilisin Kexin-9 Inhibitor Use

Abstract: Although the proprotein convertase subtilisin kexin-9 inhibitors (PCSK9i) were shown to significantly lower low-density lipoprotein and reduce atherosclerotic cardiovascular disease events in clinical trials, there is a dearth of use data on these agents in real-world settings. This study compares PCSK9i use in a population of real-world patients with atherosclerotic cardiovascular disease or familial hypercholesterolemia. This was a matched cohort study of adult patients who were dispensed a PCSK9i along with adult patients who did not receive a PCSK9i. PCSK9i patients were matched on a propensity to have received a PCSK9i score up to 1:10 to non-PCSK9i patients. The primary outcomes were changes in cholesterol levels. Secondary outcomes included a composite outcome of all-cause mortality, major cardiovascular events, and ischemic strokes along with health care utilization during follow-up. Adjusted conditional, multivariate Cox proportional hazards, and negative binomial modeling were performed. Ninety-one PCSK9i patients were matched to 840 non-PCSK9i patients. Seventy-one percent of PCSK9i patients either discontinued or switched PCSK9i therapy. PCSK9i patients had greater median reductions in low-density lipoprotein (−73.0 mg/dL vs. −30.0 mg/dL) and total (−77.0 vs. −31.0) cholesterol (both P < 0.001). No adjusted between-group differences in the composite outcome or individual components of the composite outcome were identified (all P > 0.05). PCSK9i patients had a lower rate of medical office visits during follow-up (adjusted incidence rate ratio = 0.61, P = 0.019). These findings support the effectiveness of PCSK9i therapy in real-world settings but suggest that use may be limited by PCSK9i adverse reactions and patient cost barriers.