Comparative Effectiveness of Hypoglycemic Medications Among Veterans

BACKGROUND: The efficacy of diabetic medications among patients with multiple comorbidities is not tested in randomized clinical studies. It is important to monitor the performance of these medications after marketing approvals. OBJECTIVES: To investigate the risk of all-cause mortality associated with prescription of hypoglycemic agents. METHODS: We retrospectively examined data from 17,773 type 2 diabetic patients seen from March 2, 1998, to December 13, 2010, in 3 Veterans Administration medical centers. Severity was measured using patients’ inpatient and outpatient comorbidities during the last year of visits. Severity-adjusted logistic regression was used to measure the odds ratio for mortality within the study period. RESULTS: Patients’ severity of illness correctly classified mortality for 89.8% of the patients (P less than 0.0001). Being younger, married, and white decreased severity adjusted risk of mortality. Exposure to the following medications increased severity adjusted risk of mortality: glyburide (odds ratio [OR]=1.804, 95% CI from 1.518 to 2.145), glipizide (OR=1.566, 95% CI from 1.333 to 1.839), rosiglitazone (OR=1.805, 95% CI from 1.378 to 2.365), chlorpropamide (OR=3.026, 95% CI from 1.096 to 8.351), insulin (OR=2.382, 95% CI from 2.112 to 2.686). None of the other medications (metformin, acarbose, glimepiride, pioglitazone, repaglinide, troglitazone, or dipeptidyl peptidase-4) were associated with excess mortality beyond what could be expected from the patients’ severity of illness or demographic characteristics. The reported excess mortality could not be explained away by use of other concurrent, nondiabetic classes of medications. CONCLUSIONS: Our findings suggest chlorpropamide, glipizide, glyburide, insulin, and rosiglitazone increased severity-adjusted mortality in veterans with type 2 diabetes. A decision aid that could optimize selection of hypoglycemic medications based on patients’ comorbidities might increase patients’ survival.