Background: It remains controversial whether adding ezetimibe to low/moderate-intensity statins has a more beneficial impact on the treatment efficacy and safety of patients with existing atherosclerotic cardiovascular disease (ASCVD) compared to high-intensity statin regimens.

Hypothesis: A combination of low/moderate-intensity statins plus ezetimibe might be more effective and safer than high-intensity statin monotherapy.

Methods: We searched databases for randomized controlled trials comparing lipid profile alterations, drug-related adverse events, and MACE components between high-intensity statin monotherapy and low/moderate-intensity statin plus ezetimibe combination therapy. Pooled risk ratios (RR), mean differences (MD), and 95% confidence intervals (95% CI) were estimated using a random-effects model.

Results: Our comprehensive search resulted in 32 studies comprising 6162 patients treated with monotherapy against 5880 patients on combination therapy. Combination therapy was more effective in reducing low-density lipoprotein cholesterol (LDL-C) levels compared to monotherapy (MD = -6.6, 95% CI: -10.6 to -2.5); however, no significant differences were observed in other lipid parameters. Furthermore, the combination therapy group experienced a lower risk of myalgia (RR = 0.27, 95% CI: 0.13-0.57) and discontinuation due to adverse events (RR = 0.61, 95% CI: 0.51-0.74). The occurrence of MACE was similar between the two treatment groups.

Conclusions: Adding ezetimibe to low/moderate-intensity statins resulted in a greater reduction in LDL-C levels, a lower rate of myalgia, and less drug discontinuation compared to high-intensity statin monotherapy in patients with existing cardiovascular disease. However, according to our meta-analysis, the observed reduction in LDL-C levels in the combination group did not correlate with a reduction in MACE compared to the high-intensity statin group.