Preoperative glucose as a screening tool in patients without diabetes

Background Although hyperglycemia has been associated with poor postoperative outcomes, preoperative hyperglycemia is not used as a screening tool in patients without diabetes. We evaluated preoperative glucose as a marker for postoperative outcomes in patients without diabetes to assess its usefulness as a potential screening tool. Materials and methods Clinical characteristics for a sample of 6683 patients without diabetes who underwent nonemergent vascular and general surgery were collected from the American College of Surgeons National Surgical Quality Improvement Program, Brigham and Women's Hospital database. Last glucose measured within 30 d before surgery was the main predictor variable with postoperative infection within 30 d as the primary outcome. Results For patients without known diabetes with preoperative glucose of 100-139 and 140-179 mg/dL, postoperative infection rates were significantly higher (9.33% and 10.16%, respectively) than that of patients with preoperative glucose of 70-99 mg/dL (5.62%, P < 0.001). The risk-adjusted odds of postoperative infection increased by 40% (95% CI, 13%-72%) for each 40 mg/dL increase in preoperative glucose over the range 70-179 mg/dL. Follow-up data demonstrated that 15% of patients with preoperative glucose ≥100 mg/dL were diagnosed with diabetes within 1 y after surgery. Conclusions In patients without known diabetes, preoperative glucose is a significant marker for postoperative complications even at moderate levels of hyperglycemia. Some of these patients likely had prediabetes or unrecognized diabetes at the time of surgery. Further studies are needed to determine whether such screening and follow-up of preoperative hyperglycemia in all patients would be effective in lowering complication rates.