Prediabetes in patients treated with antipsychotic drugs.

BACKGROUND: In 2010, the American Diabetes Association (ADA) proposed that individuals with fasting glucose level of 100-125 mg/dL (5.6-6.9 mmol/L) or glucose level of 140-199 mg/dL (7.8-11.0 mmol/L) 2 hours after a 75-g oral glucose tolerance test or hemoglobin A(1c) 5.7%-6.4% be classified as prediabetic, indicating increased risk for the emergence of diabetes mellitus. At the same time, the ADA formulated guidelines for the use of metformin for the treatment of prediabetes.

OBJECTIVE: To determine the prevalence of prediabetes in a cohort of psychiatrically ill adults receiving antipsychotics and to compare the clinical and metabolic features of prediabetic patients with those of patients with normal glucose tolerance and those with diabetes mellitus.

METHOD: The 2010 ADA criteria were applied to a large, consecutive, single-site European cohort of 783 adult psychiatric inpatients (mean age: 37.6 years) without a history of diabetes who were receiving antipsychotics. All patients in this cross-sectional study underwent measurement of body mass index (BMI), waist circumference, oral glucose tolerance test, and fasting insulin and lipids from November 2003 through July 2007.

RESULTS: 413 patients (52.8%) had normal glucose tolerance, 290 (37.0%) had prediabetes, and 80 (10.2%) had diabetes mellitus. The fasting glucose and/or hemoglobin A(1c) criteria were met by 89.7% of prediabetic patients. A statistically significant intergroup gradient from normal glucose tolerance to prediabetes and from prediabetes to diabetes mellitus was observed for waist circumference, triglycerides, fasting insulin levels, and frequency of metabolic syndrome (P = .02 to P < .0001). Only 19/290 prediabetic patients (6.6%) met the 2010 ADA criteria for treatment with metformin.

CONCLUSIONS: Prediabetes is highly prevalent in adults treated with antipsychotic drugs and correlates with markers of increased intraabdominal adiposity, enhanced lipolysis, and insulin resistance. Criteria for using metformin to prevent the emergence of diabetes mellitus may need to be revised for this population.