Introduction: Dual antiplatelet therapy (DAPT) after percutaneous coronary intervention (PCI) reduces myocardial infarctions but increases bleeding. Guidelines recommend using risk scores to assess bleeding risk, but none have been validated in self-reported Black patients. We compared 1) post-discharge bleeding between US Black and White patients, and 2) the ability of three risk scores to predict bleeding between them. Methods: The PRiME-GGAT prospective cohort study enrolled patients (2014-2019) who underwent PCI and followed them for one year. Variables measured at PCI were included in the PRECISE-DAPT, PARIS, and ARC-HBR scores. The outcome was post-discharge BARC 2-5 events. Incidence rates were compared between Black and White patients, using incidence rate ratios (IRRs). Proportional hazards models measured the effect of self-reported Black ethnicity, adjusted for bleeding risk factors. Risk scores were compared between Black and White patients using: 1) IRRs, 2) Harrell’s C-indices, and 3) Kendall’s tau-b coefficients (τ b ). τ b was not measured for the binary ARC-HBR score. Results: Of 1529 included patients, 342 (22.4%) self-reported as Black. The incidence rate was higher among Black patients compared to White patients (22.7 versus 16.3, respectively, per 100 person-years; IRR 1.39; 95% CI, 1.01-1.90). After adjustment, self-reported Black ethnicity was not a predictor of bleeding. For both groups, IRRs were largest for PRECISE-DAPT. Between Black and White patients, respectively, C-index was 0.65 vs. 0.61 for PRECISE-DAPT, 0.63 vs. 0.61 for PARIS, and 0.60 vs. 0.59 for ARC-HBR; and τ b , respectively, was 0.71 vs. 0.64 for PRECISE-DAPT, and 0.79 vs. 0.86 for PARIS. Conclusions: Post-discharge bleeding from DAPT was greater for Black patients, compared with White patients, but this difference was not present after adjustment. PRECISE-DAPT was superior among Black patients, but PARIS was superior among White patients.
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