We identified a total of 279 patients for the abiraterone and the enzalutamide cohorts matched 1:1 on age (<70, 70-74, 75-79 or ≥80 years), race, drug start year (≤2018 or ≥2020), PSA at diagnosis (<50 or ≥50 ng/mL), CCI excluding cancer diagnosis (<5 or ≥5), and Gleason score (<8 or ≥8) (eTable 4 in Supplement 1). The gene discussed is KLK3; the disease is cancer.