Pell, Jill P.

Background: Effective lipid lowering therapy reduces deaths due to atherosclerotic vascular disease (ASCVD). Proprotein convertase subtilsin/kexin type 9 inhibitor (PCSK9i) drugs have emerged as effective add-on therapy to lower low-density lipoprotein (LDL) levels. Although the use of PCSK9i is limited by cost, PCSK9i use in a low-cost healthcare system [Veteran Health Affairs (VHA)] is unknown. Methods: We queried a cohort of US Veterans with coronary artery disease (CAD), PAD or CeVD receiving outpatient care (January 2016 – December 2019) at 124 VHA medical centers to evaluate the initiation of PCSK9i. We fit a mixed effects logistic regression model [with results presented as odds ratio (OR)] to evaluate the association of social deprivation (assessed by median household income and community deprivation index), the patient’s primary diagnosis and VHA medical center enrollment with PCSK9i initiation. Findings: From 519,566 patients (median age 74 years), 337,766 (65%), 79,926 (15%) and 101,874 (20%) had CAD, PAD and CeVD. Among 2,115/519,566 (0.4%) initiated with PCSK9i therapy, 84.3% had CAD, while only 7.2% and 8.5% had PAD and CeVD respectively. PCSK9i initiation was lower in those earning $40,000 - $80,000 [OR 1.13 (1.01 – 1.27)] or > $80,000 [OR 1.41 (1.14 – 1.75)]. Even moderate community deprivation [OR 0.87 (0.77 – 0.97)] was associated with lower PCSK9i therapy. Compared to CAD patients, PAD [OR 0.50 (0.35 – 0.70)] and CeVD [OR 0.23 (0.15 – 0.37)] were less likely to receive PCSK9i. Interpretation: Despite low co-pay, PCSK9i initiation rates among US veterans, nationwide, is very low. PAD and CeVD patients are much less likely to receive PCSK9i therapy. Household income and community deprivation influence PCSK9i use.