The impact of diabetes on postoperative outcomes following spine surgery: A meta-analysis of 40 cohort studies with 2.9 million participants

Although diabetes mellitus (DM) is considered to be an important prognostic factor in spinal surgery, the relationship between these two factors remains unclear. The purpose of this study was to investigate whether diabetes is associated with an increased risk of postoperative complications in patients undergoing spinal surgery.We systematically searched the PubMed, Embase, and Cochrane Library for relevant articles published on or before December 25, 2021. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using random effects meta-analysis. The primary outcome was the risk of postoperative complications following spinal surgery, including postoperative infection and reoperation. Furthermore, we conducted subgroup analyses and leave-one-out sensitivity analyses to explore the main sources of heterogeneity and the stability of the results.A total of 40 cohort studies including 2,998,891 participants met the inclusion criteria. Meta-analysis showed that diabetes was significantly associated with postoperative infection (OR 2.21, 95% CI 1.70-2.88, p < 0.001) and reoperation (OR 1.35, 95% CI 1.12-1.64, p = 0.002). Furthermore, the results also found that diabetes was significantly associated with surgery-related death (OR 1.61, 95% CI 1.13-2.30, p = 0.008) and transfusions (OR 1.39, 95% CI 1.11-1.75, p = 0.005), whereas diabetes failed to account for nervous system complications (OR 1.12, 95% CI 0.82-1.52, p = 0.470) and embolism (OR 1.15, 95% CI 0.83-1.60, p = 0.386) for patients following spine surgery. These results were further confirmed by the trim-and-fill procedure and leave-one-out sensitivity analyses.Diabetes appears to be a risk factor for postoperative infection and reoperation for patients following spinal surgery. Special attention should be devoted to reducing the occurrence of postoperative complications in diabetic patients undergoing spinal surgery.