Factors associated with pcsk9 inhibitor initiation among us veterans

BACKGROUND: Few adults at high risk for atherosclerotic cardiovascular disease events use a PCSK9i (proprotein convertase subtilisin/kexin type 9 inhibitor). METHODS AND RESULTS: Using data from the US Veterans Health Administration, we identified veterans who initiated a PCSK9i between January 2018 and December 2019, matched 1:4 to veterans who did not initiate this medication over this time period (case-cohort study). Two cohorts of veterans were analyzed: (1) atherosclerotic cardiovascular disease, with a most recent low-density lipoprotein cholesterol (LDL-C) ≥70 mg/dL; and (2) severe hypercholesterolemia (ie, familial hypercholesterolemia or any prior LDL-C ≥190 mg/dL, with most recent LDL-C ≥100 mg/dL). Conditional logistic regression was used to analyze factors associated with PCSK9i initiation, adjusting for all factors, simultaneously. There were 2394 initiators and 9576 nonini-tiators in the atherosclerotic cardiovascular disease cohort (median LDL-C, 141 and 96 mg/dL, respectively; P<0.001). Factors associated with a higher likelihood of PCSK9i initiation included age 65 to <75 versus <65 years, highest versus lowest quartile of median area-level income, familial hypercholesterolemia, former statin use, and current ezetimibe use. PCSK9i initiation was lower among veterans of a race/ethnicity other than non-Hispanic White. There were 245 initiators and 980 noninitiators in the severe hypercholesterolemia cohort (median LDL-C, 183 and 151 mg/dL, respectively; P<0.001). Age ≥75 versus <65 years, history of chronic kidney disease, former statin use, and current ezetimibe use were associated with a higher likelihood of PCSK9i initiation. CONCLUSIONS: Several patient-level factors, including age, sex, and race/ethnicity, were significantly associated with PCSK9i initiation, suggesting an unmet treatment need in several patient groups.