BACKGROUND
Failure to manage diabetes mellitus receiving monotherapy increases as the duration of the disease is protracted, and in many cases it becomes inevitable to introduce combined therapies. However, compliance of the patients tends to decrease. We conducted a clinical study to compare the efficacy and safety of preconstituted and fixed combination therapy of glimepiride plus metformin to those of free combination therapy. METHODS: Two hundred and thirteen patients with type 2 diabetes who had been diagnosed at least six months ago were randomly assigned either to a fixed group or a free group. The initial dosage was chosen according to the previous treatment history and then adjusted every two weeks following a predefined titration algorithm to meet the target mean fasting glucose levels (140 mg/dL). The medications were given for 16 weeks. The primary endpoint was the change in HbA1c level from baseline to week 16. Various parameters were checked as secondary outcome measures and safety criteria. RESULTS: HbA1c level of the fixed group and the free group decreased by 1.09% and 1.08%, respectively. The 95% CI of the changes' difference between the two groups (-0.21%, +0.19%) was within the predefined equivalence interval (-0.5%, +0.5%). Secondary outcome measures (the changes of fasting and postprandial plasma glucose level, response rate and compliance) and safety criteria (frequency of hypoglycemia and adverse reactions) were similar between the two groups. CONCLUSION: Fixed combination of glimepiride/metformin is as effective and safe therapy as free combination in type 2 diabetes patients.