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

BACKGROUND: 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.

OBJECTIVE: This study examined the effect of metformin treatment on the percentage of patients experiencing postoperative hyperglycemia after elective colon cancer surgery.

DESIGN: This was a randomized, double-blind, placebo-controlled trial.

SETTINGS: The study was conducted at Slagelse Hospital in Slagelse, Denmark.

PATIENTS: Patients without diabetes planned for elective surgery for colon cancer were included.

INTERVENTIONS: Patients received metformin (500 mg 3× per day) or placebo for 20 days before and 10 days after surgery.

MAIN OUTCOME MEASURES: 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.

RESULTS: 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.

LIMITATIONS: 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.

CONCLUSIONS: 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 .