Importance: Surgical complications associated with perioperative hyperglycemia are conventionally associated with diabetes, but, paradoxically, prior cohort studies have found that patients without diabetes have greater risk of complications at similar levels of hyperglycemia compared with patients with diabetes.
Objective: To describe the association between perioperative hyperglycemia and surgical complications in a population of surgical patients without diabetes receiving routine blood glucose testing and insulin administration and to evaluate the potential correlation of perioperative hyperglycemia.
Design, setting, and participants: This retrospective cohort study of National Surgical Quality Improvement Program-defined complications after operation took place at a single academic medical center hospital from January 2013 to October 2016. Consecutive patients undergoing general, vascular, and gynecologic operations who were expected to have at least a 48-hour admission were included. Hyperglycemia was defined as blood glucose level of 140 mg/dL or higher within 24 hours after surgery. Multivariate regression was used to assess the association of hyperglycemia and complications, stratified by hyperglycemia severity and adjusted for diabetes status. Analysis began in February 2022.
Exposures: Routine blood glucose testing and insulin administration.
Main outcomes and measures: The main outcomes are odds of experiencing perioperative hyperglycemia and postoperative complication, comparing patients with and without diabetes.
Results: A total of 7634 patients (mean [SD] age, 53.5 [15.1] years; 6664 patients without diabetes [83.3%] and 970 patients with diabetes [17.7%]) underwent general (6204 [81.3%]), vascular (208 [2.7%]), and gynecologic (1222 [16%]) operations. Of these, 5868 (77%) had blood glucose testing (4899 individuals without diabetes [73.5%] and 969 [99.9%] with diabetes). Hyperglycemia occurred in 882 patients with diabetes (91%) and 2484 patients without diabetes (50.7%). Of those with blood glucose level more than 180 mg/dL, 1388 (72.7%) received insulin (658 patients with diabetes who had hyperglycemia [91%] and 680 patients without diabetes who had hyperglycemia [61%]). Adjusted odds of experiencing a complication were 83% greater for patients without vs with diabetes at blood glucose level of 140 to 179 mg/dL (odds ratio, 1.83 [95% CI, 0.93-3.6]), 49% greater for blood glucose level of 180 to 249 mg/dL (odds ratio, 1.49 [95% CI, 1.06-2.11]), and 88% greater for blood glucose level more than 250 mg/dL (odds ratio, 1.88 [95% CI, 1.11-3.17]). A similar trend was observed for serious complications. Insulin may mitigate the association of hyperglycemia and complications in patients without diabetes.
Conclusions and relevance: In this study, with near universal blood glucose testing and frequent insulin use, patients without diabetes paradoxically had worse outcomes than patients with diabetes at similar levels of hyperglycemia. Insulin may mitigate this effect and broader use may improve outcomes.