Metabolic syndrome and surgical complications: A systematic review and meta-analysis of 13 million individuals

Background: Metabolic syndrome is characterised by the presence of at least three of the five following components: insulin resistance, obesity, chronic hypertension, elevated serum triglycerides and decreased high-density lipoprotein cholesterol concentrations. It is estimated to affect 1 in 3 people around the globe and reported to affect 46% of surgical patients. For people with metabolic syndrome who undergo surgery, an emerging body of literature points to significantly poorer postoperative outcomes compared with non-affected populations. The aim of this study is to review the current evidence on risks of surgical complications in patients with metabolic syndrome compared to those without metabolic syndrome. Methods: Systematic review and meta-analysis using PRISMA and AMSTAR reporting guidelines. Results: The meta-analysis included 63 studies involving 1,919,347 patients with metabolic syndrome and 11,248,114 patients without metabolic syndrome. Compared to individuals without the condition, individuals with metabolic syndrome were at an increased risk of mortality (OR 1.75 95% CIs [1.36-2.24]; P <0.01); all surgical site infection types as well as dehiscence (OR 1.64 95% CIs [1.52 -1.77]; P <0.01); cardiovascular complications (OR 1.56 95% CIs [1.41 -1.73]; P <0.01) including myocardial infarction, stroke, cardiac arrest, cardiac arrythmias and deep vein thrombosis; increased length of hospital stay (MD 0.65 95% CIs [0.39-0.9]; P <0.01); and hospital readmission (OR 1.55 95% CIs [1.41-1.71]; P <0.01). Conclusion: Metabolic syndrome is associated with a significantly increased risk of surgical complications including mortality, surgical site infection, cardiovascular complications, increased length of stay and hospital readmission. Despite these risks and the high prevalence of metabolic syndrome in surgical populations there is a lack of evidence on interventions for reducing surgical complications in patients with metabolic syndrome. The authors suggest prioritising interventions across the surgical continuum that include (1) preoperative screening for metabolic syndrome; (2) surgical prehabilitation; (3) intraoperative monitoring and management; and (4) postoperative rehabilitation and follow-up.