Adverse complications of cervical spinal fusion in patients with different types of diabetes mellitus: a retrospective nationwide inpatient sample database cross-sectional study

Background: Diabetes mellitus (DM) is a prevalent chronic condition that influences spine surgery outcomes. The impact of type I and type II DM on adverse postoperative outcomes, mortality, prolonged length of stay (LOS), and increased in-hospital costs following cervical fusion surgery remains unclear in the past decade. This study aims to determine the specific effect of different classifications of DM on postoperative complications in patients experiencing cervical fusion surgery. Method: Data from the Nationwide Inpatient Sample database was acquired between 2010 and 2019. Patients experiencing cervical fusion were included and classified as having type I DM, type II DM, or neither. Patient demographics, hospital characteristics, operative variables, comorbidities, complications, and other postoperative outcomes were assessed. Propensity score matching analysis was used to balance baseline differences. Univariate and multivariate logistic regression were employed to determine the risk of postoperative outcomes in patients with different classifications of DM. Result: A total of 267 174 cervical spinal fusions were identified (224 255 were patients without DM, 670 patients had type I DM, and 42 249 patients had type II DM). After propensity score matching, the multivariate analysis of non-DM and type I DM patients shows a significant difference in pneumonia (P=0.020). However, type II DM served as an independent predictor of an increased risk of acute cerebrovascular disease (P=0.001), acute myocardial infarction (P=0.014), pneumonia (P=0.045), continuous trauma ventilation (P=0.016), chest pain (P<0.001), urinary tract infection (P<0.001), transfusion (P=0.005) and dysphagia (P=0.013), prolonged LOS (P<0.001), and increased costs (P=0.008). Conclusion: Using non-DM patients as a reference, the type II DM group demonstrated a higher risk of postoperative complications than the type I DM group among patients receiving cervical fusion surgery. This vital distinction could enhance risk stratification and guidance for patients diagnosed with DM before cervical fusion surgery.