The magnitude of weight loss induced by metformin is independently associated with BMI at baseline in newly diagnosed type 2 diabetes: Post-hoc analysis from data of a phase IV open-labeled trial.

BACKGROUND: The impact of metformin on body weight is variable in T2DM patients among studies. The reasons for the discrepancies are still unknown.
OBJECTIVES: We aimed to find out the possible predictive factors of weight change induced by metformin based on an analysis of a phase IV open-labeled trial.
MATERIAL AND METHODS: We performed a sub-analysis from a prospective, multi-center phase IV open-labeled study in which 371 Chinese newly-diagnosed type 2 diabetes patients received 16 weeks' extended-release metformin monotherapy. The clinical characteristics including weight and laboratory assessments of subjects were collected every 4 weeks. The weight changes from baseline to week 4, 8, 12 and 16 were calculated respectively. The patients were divided into 4 groups by quartile statistics method according to magnitudes of weight change.
RESULTS: Of 371 enrolled patients, 324 patients had the weight records from baseline to week 16. The weight decreased gradually with each visit (p < 0.001) and the average weight loss was 2 kg after 16 weeks' treatment of metformin. The patients with higher BMI and bigger waist circumference at baseline showed a more pronounced weight loss. However, the magnitudes of weight loss were independently associated with BMI at baseline only.
CONCLUSIONS: Metformin can lead to weight loss gradually in newly-diagnosed type 2 diabetes patients. The magnitude of weight loss was independently and only associated with baseline BMI.