Perioperative Metformin Treatment to Reduce Postoperative Hyperglycemia After Colon Cancer Surgery: A Randomized Clinical Trial

Surgery induces a stress response, causing insulin resistance that may result in postoperative hyperglycemia, which is associated with increased incidence of complications, longer hospitalization, and greater mortality. This study examined the effect of metformin treatment on the percentage of patients experiencing postoperative hyperglycemia after elective colon cancer surgery. This was a randomized, double-blind, placebo-controlled trial. The study was conducted at Slagelse Hospital in Slagelse, Denmark. Patients without diabetes planned for elective surgery for colon cancer were included. Patients received metformin (500 mg 3× per day) or placebo for 20 days before and 10 days after surgery. Blood glucose levels were measured several times daily until the end of postoperative day 2. The main outcome measures were the percentage of patients who experienced at least 1 blood glucose measurement >7.7 and 10 mmol/L, respectively. Rates of complications within 30 days of surgery and Quality of Recovery-15 scores were also recorded. Of the 48 included patients, 21 patients (84.0%) in the placebo group and 18 patients (78.3%) in the metformin group had at least 1 blood glucose measurement >7.7 mmol/L ( p = 0.72), and 13 patients (52.0%) in the placebo group had a measurement >10.0 mmol/L versus 5 patients (21.7%) in the metformin group ( p = 0.04). No differences in complication rates or Quality of Recovery-15 scores were seen. The number of patients in the study was too low to detect a possible difference in postoperative complications. Blood glucose was measured as spot measurements instead of continuous surveillance. In patients without diabetes, metformin significantly reduced the percentage of patients experiencing postoperative hyperglycemia, as defined as spot blood glucose measurements >10 mmol/L after elective colon cancer surgery. See Video Abstract .