BACKGROUNDPatients with type 2 diabetes mellitus often take multiple anti-diabetic drugs for a long period. Fixed dose combination (FDC) therapy is expected to improve drug adherence for patients with diabetes. The effect of switching from a loose dose combination (LDC) regimen to an FDC regimen at equivalent dosage on glycemic control has not been evaluated fully. Therefore, we investigated the effect of switching from LDC to FDC at equivalent dosage for 6 months on glycemic control in Japanese patients with type 2 diabetes.METHODSThirty-eight Japanese patients with type 2 diabetes who were taking anti-diabetic drugs including pioglitazone + metformin, pioglitazone + alogliptin, or pioglitazone + glimepiride were enrolled. These drugs were switched to an FDC of Metact®, Liobel® or Sonias®, respectively, at equivalent dosage. Other anti-diabetic drugs and units of insulin were not changed during the study if possible. HbA1c and body weight were measured 0, 2, 4 and 6 months after switching from an LDC to FDC. We also conducted a questionnaire survey 2 months after the start of the FDC regimen.RESULTSHbA1c levels at 2, 4, and 6 months were not significantly changed compared with prior to switching from an LDC to FDC regimen. Moreover, 74.2% of patients considered decreasing the number of drugs to be "very good" or "good".CONCLUSIONHbA1c levels did not differ between patients receiving LDC and FDC therapy at equivalent dosage in this study.