Association between oral antidiabetic use, adverse events and outcomes in patients with type 2 diabetes

To quantify adverse events (AEs) associated with the use of metformin (MET), sulphonylureas (SUs) and thiazolidinediones (TZDs) in a usual care setting, and to assess the relationship of AEs to treatment patterns and glycaemic response in patients with type 2 diabetes.

An electronic medical record database was used to identify patients with type 2 diabetes age >or=18 years from 1996 to 2005. Patients naïve to oral antidiabetic therapy were followed for 395 days postinitiation of MET, SU or TZD treatment. AEs related to study drugs were evaluated during the follow-up period. Baseline and follow-up A1C levels were compared by drug regimen. Associations between the change in A1C, drug regimen changes and AEs were evaluated.

A total of 14,512 patients (mean age 60.8 years, 52.9% female) were identified. During the follow-up period, 12.7% of patients experienced an AE (8.6% MET, 15.9% SU and 19.8% TZD patients). SU and TZD patients were more likely to experience an AE than MET (p < 0.001) patients. AEs did not significantly influence A1C outcomes, although MET and SU patients experiencing an AE were more likely to add-on therapy (odds ratio (OR) = 1.34 and OR = 1.37, respectively; p < 0.05) than those without an AE. MET patients with AEs were more likely to switch therapy (OR = 1.91; p < 0.05) than those without an AE.

The occurrence of AEs did not significantly impact glycaemic response to therapy. However, AEs may lead to greater treatment switches for patients receiving MET and add-on therapy for MET-treated and SU-treated patients.