Comparative efficacy of LDL-C-lowering therapies in first-time vs. recurrent myocardial infarction prevention: a meta-analysis of large-scale randomized controlled trials.
AIMS: Reducing elevated low-density lipoprotein cholesterol (LDL-C) is central to global efforts to prevent myocardial infarction (MI). While many studies have evaluated LDL-C-lowering therapies in first-time and recurrent MI prevention, direct comparisons of their relative efficacy are lacking. Therefore, we conducted a systematic review and meta-analysis to compare the efficacy of LDL-C-lowering therapies in first-time vs. recurrent MI prevention. METHODS AND RESULTS: We searched three databases until 30 November 2024, for randomized controlled trials (RCTs) with at least 1000 patient-years of follow-up. Efficacy was quantified as relative risk (RR) with 95% confidence intervals (CIs). Differences in benefit magnitude were assessed using Cochran's Q test. Data were pooled with a random-effects model, and heterogeneity was measured using the I2 statistic. Additionally, we applied the Cochrane Risk of Bias Tool to evaluate study quality and utilized the GRADE method to assess the certainty of the evidence. This study included 22 large-scale RCTs involving 180 304 participants. In first-time MI prevention, LDL-C-lowering therapies achieved a remarkable 38% reduction in MI risk [12 RCTs; 79 604 participants; RR, 0.62 (95% CI, 0.55-0.69); P < 0.001]. In recurrent MI prevention, these therapies were associated with a more modest but significant 16% risk reduction [11 RCTs; 100 700 participants; RR, 0.84 (95% CI, 0.80-0.88); P < 0.001]. Importantly, the benefit magnitude between the two groups was significantly different (Q = 22.63; P < 0.001), highlighting the greater relative benefit in first-time MI prevention. Furthermore, the robustness of our findings was consistently supported by leave-one-out analyses, the absence of publication bias, high-quality GRADE evidence, and subgroup and sensitivity analyses. CONCLUSION: Our findings suggest that LDL-C-lowering therapies may offer a greater benefit in preventing first-time MI compared with recurrent MI.