The Effect of Type 2 Diabetes Mellitus on Perioperative Neurocognitive Disorders in Patients Undergoing Elective Noncardiac Surgery under General Anesthesia. A Prospective Cohort Study

Background and Aims: Preliminary evidence suggests a possible relationship between type 2 diabetes mellitus (T2DM) and perioperative neurocognitive disorders (NCD). We sought to investigate whether patients with T2DM, undergoing elective noncardiac surgery under general anesthesia, are at increased risk of perioperative NCD. Material and Methods: A prospective cohort study was designed. One-hundred and forty-four patients with T2DM and 144 healthy controls were recruited. Controls were matched for sex, age, type of operation, and educational background. Postoperative delirium (POD), delayed neurocognitive recovery and postoperative NCD were evaluated. Results: Two hundred twenty-eight patients were analyzed. Compared to controls, patients with T2DM were diagnosed with higher rates of NCD preoperatively (n = 96 vs. n = 26. P < 0.05) and higher POD up to 4 days postoperatively (n = 204 vs. n = 68, P < 0.05). Increased rates of delayed neurocognitive recovery and postoperative NCD were recorded in patients with T2DM up to 9 months postoperatively (n = 473 vs. n = 192, P < 0.05). Insulin-dependent patients had higher rates of POD on the second (n = 38 vs. n = 24, P < 0.05) and third day (n = 27 vs. n = 16, P < 0.05) when compared to noninsulin-dependent patients. Logistic multivariable analysis revealed that patients with T2DM are at increased risk for postoperative cognitive disorders. Conclusion: Patients with type 2 diabetes mellitus appear to be at a higher risk of perioperative NCDs up to 9 months after elective noncardiac surgery under general anesthesia.