Perez Tagle Tejeda, Alfredo

Abstract Aims Routine aspirin use for primary prevention yields modest cardiovascular benefit but increases bleeding risk in average-risk adults. Whether individuals with elevated lipoprotein(a) [Lp(a)] levels or high-risk LPA variants derive greater benefit remains uncertain. Methods and results Following Cochrane and PRISMA guidelines, we systematically searched PubMed/MEDLINE, Embase, and Cochrane Central for studies of adults without ASCVD, elevated Lp(a) (≥50 mg/dL), high-risk LPA genotypes, or elevated genetic risk scores, comparing aspirin vs. no aspirin use. Random-effects meta-analyses using restricted maximum-likelihood (REML) estimation with Hartung–Knapp–Sidik–Jonkman (HKSJ) adjustment were used to pool hazard ratios (HR) and 95% confidence intervals (CI). In six studies, 6628 participants were included. Pooled random effects showed no significant reduction in major adverse cardiovascular events (MACE) with aspirin (HR = 0.60; 95% CI 0.31–1.17; P = 0.1) or clinical bleeding events (HR = 1.24; 95% CI 0.83–1.87; P = 0.18). Subgroup analyses showed a nonsignificant reduction MACE among elevated Lp(a) (HR = 0.63; 95% CI 0.16 to 2.49; P = 0.284) and statistically significant reduction among LPA rs3798220 carriers (HR = 0.37; 95% CI 0.19 to 0.71; P = 0.003), though this finding was not consistent in the sensitivity analyses. Conclusion Among adults without ASCVD but with elevated Lp(a) or high-risk LPA genotypes, aspirin use did not confer a statistically significant cardiovascular benefit and was associated with numerically higher bleeding risk. The apparent reduction seen in rs3798220 carriers was inconsistent and likely reflects small-sample bias.