Diabetes mellitus and the risk of sudden cardiac death: A systematic review and meta-analysis of prospective studies

Background: Although diabetes mellitus is an established risk factor for myocardial infarction and stroke, data on the association with sudden cardiac death are less extensive and the findings have not been entirely consistent. We therefore conducted a systematic review and meta-analysis of prospective studies on diabetes mellitus and risk of sudden cardiac death. Methods and results: PubMed and Embase databases were searched up to July 18th 2017. Prospective studies that reported adjusted relative risk (RR) estimates and 95% confidence intervals (CIs) for the association between a diabetes diagnosis or pre-diabetes and risk of sudden cardiac death were included. Summary RRs were estimated by use of a random effects model. Nineteen population-based prospective studies (11 publications) (3610 cases, 249,225 participants) and 10 patient-based prospective studies (2713 cases, 55,098 participants) were included. The summary RR for diabetes patients vs. persons without diabetes was 2.02 (95% CI: 1.81-2.25, I-2=0%, (Pheterogeneity) = 0.91) in the population-based studies. The summary RR was 1.23 (95% CI: 1.05-1.44, I-2=6%, (Pheterogeneity) = 0.34) for the association between pre-diabetes and sudden cardiac death (n=3 studies, 1000 sudden cardiac deaths, 18,360 participants). In the patient-based studies, the summary RR of sudden cardiac death for diabetes patients vs. patients without diabetes was 1.75 (95% CI: 1.51-2.03, I-2=39%, (Pheterogeneity) = 0.10) for all patients combined, 1.63 (95% CI: 1.36-1.97, I-2=39%, n=5) for coronary heart disease patients, and 1.85 (95% CI: 1.48-2.33, I-2=0%, n=3) for heart failure patients. Conclusions: These results suggest that diabetes patients are at an increased risk of sudden cardiac death both in the general population and among different patient groups. (C) 2018 The Italian Society of Diabetology, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition, and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved.