Objective:To assess the association between diabetes mellitus and the risk of sudden cardiac death (SCD), and to identify potential contributing factors.Methods:This meta-analysis was an updated version of the original study Diabetes mellitus and the risk of sudden cardiac death： a systematic review and meta-analysis of prospective studies. The original review included all eligible case-control and cohort studies published in PubMed and Embase up to 2017 that investigated the association between diabetes and SCD risk. In this updated study, newly published studies were added, including those available in PubMed, Embase, China National Knowledge Infrastructure (CNKI), and WANFANG MED ONLINE up to December 3, 2023. Search terms included "diabetes""glucose""sudden cardiac death" "cardiac arrest" and their Chinese equivalent. The primary outcome was the risk of SCD, while factors such as country, ethnicity, skin color, follow-up duration, left ventricular ejection fraction (LVEF), baseline comorbidities, and other relevant variables were analyzed as potential influencing factors. Relative risk ( RR) was used as the summary measure. A random-effects model was used when significant heterogeneity was detected, otherwise a fixed-effects model was used. Cochran′s Q test was used for subgroup analysis to assess the influence of factors such as region, baseline diseases, LVEF, and ethnicity (based on skin color) on the outcomes. Results:A total of 32 cohort/case-control studies with a combined sample size of 3 252 954 individuals were included. The meta-analysis showed that the risk of SCD in patients with diabetes was double that of non-diabetics ( RR=2.00, 95% CI: 1.83-2.19, P<0.001). In Asian populations, the risk of SCD in diabetic patients was 1.78 times that of non-diabetic individuals ( RR=1.78, 95% CI: 1.51-2.10), 2.05 times that of in European populations ( RR=2.05, 95% CI: 1.79-2.34), and 2.12 times that of in American populations ( RR=2.12, 95% CI: 1.82-2.47), with no statistically significant heterogeneity between regions ( P=0.287). Among individuals without other baseline comorbidities, the risk of SCD was 2.12 times higher in diabetic patients than in those without diabetes ( RR=2.12, 95% CI: 1.89-2.38). In patients with baseline coronary heart disease, the risk was 1.75 times that of non-diabetics ( RR=1.75, 95% CI: 1.45-2.11). In those with baseline heart failure, the risk was 1.92 times that of non-diabetics ( RR=1.92, 95% CI: 1.51-2.43). In patients with baseline atrial fibrillation, the risk was 4.00 times that of non-diabetic individuals ( RR=4.00, 95% CI: 1.38-11.56). In patients undergoing hemodialysis due to renal failure, the risk was 1.76 times that of non-diabetic individuals ( RR=1.76, 95% CI: 1.25-2.48), with no statistically significant heterogeneity between groups ( P=0.262). In cardiac patients with LVEF>50%, the risk of SCD in diabetic patients was 2.08 times that of non-diabetic individuals ( RR=2.08, 95% CI: 1.57-2.75), and in those with LVEF<50%, the risk was 1.69 times that of non-diabetic individuals ( RR=1.69, 95% CI: 1.30-2.18), with no statistically significant heterogeneity between groups ( P=0.277). In yellow-skinned populations, the risk of SCD in diabetic patients was 1.80 times that of healthy individuals ( RR=1.80, 95% CI: 1.73-1.87), and in white-skinned populations, it was 2.18 times that of healthy individuals ( RR=2.18, 95% CI: 1.88-2.54), with statistically significant heterogeneity between groups ( P=0.014). Conclusions:Diabetes mellitus significantly increased the risk of SCD, and this effect may be more pronounced in white-skinned populations, while region, baseline comorbidities, and LVEF had no further effect.