Abstract Body (Do not enter title and authors here): Background:
Patients with diabetes mellitus have a substantially increased risk for cardiovascular disease (CVD), even without prior events. While statin therapy is widely recommended, the precise magnitude of benefit and potential risks in this population require ongoing clarification.

Methods:
We performed a systematic review and meta-analysis of randomized controlled trials and large observational studies comparing statin therapy with placebo or usual care in adults with diabetes without established CVD. Databases searched included PubMed, CENTRAL, and EMBASE (1990–2024), adhering to PRISMA guidelines. Primary outcomes were major adverse cardiovascular events (MACE), myocardial infarction, stroke, and all-cause mortality. Risk ratios (RRs) and 95% confidence intervals (CIs) were pooled using DerSimonian-Laird random-effects models. Heterogeneity was evaluated by I² statistics.

Results:
Nine studies totaling 103,724 patients met inclusion criteria: CARDS, JUPITER, ASCOT-LLA, HOPE-3, ALLHAT-LLT, AFCAPS/TexCAPS, PROSPER, MEGA, and WOSCOPS. Statin therapy significantly reduced:
-MACE: RR 0.79 (95% CI, 0.71–0.88)
-Myocardial infarction: RR 0.77 (95% CI, 0.68–0.87)
-Stroke: RR 0.84 (95% CI, 0.75–0.94)
-All-cause mortality: RR 0.88 (95% CI, 0.80–0.97)

The overall pooled RR for the primary endpoint was 0.81 (95% CI, 0.75–0.88). Absolute risk reductions were more pronounced in older patients and those with additional risk factors. A slight increase in incident diabetes was noted but was outweighed by cardiovascular benefits. Between-study heterogeneity was low (I² < 40%).

Conclusions:
Statin therapy provides a robust cardiovascular and mortality benefit in diabetic patients without prior CVD. This evidence supports routine statin use for primary prevention, especially in older adults and those with elevated risk factors, underscoring the importance of adherence.