Background: Pioglitazone, a member of the thiazolidinedione drug family, with hypoglycemic action, is widely used for the therapy of type 2 diabetic patients.

Aims and Objectives: The effect of pioglitazone on body weight was investigated and the effects of monotherapy and combinations with other hypoglycemic agents were compared.

Methodology: A prospective study on 379 type 2 diabetic cases, who were being given pioglitazone for the first time, as either monotherapy or in combination with other oral hypoglycemic agents or insulin. Parameters were analyzed by Kruskal-Wallis test, considering p <0.05 as significant.

Results: Pioglitazone therapy resulted in weight gain, especially in females, although triglyceride and lipoprotein levels were not adversely affected. Concomitant use of pioglitazone along with insulin or any of the sulfonylurea group of drugs accounted for more weight gain; (2.57±1.4 kg) and (2.31±1.2 kg) respectively; than that by pioglitazone alone (2.23±1.3 kg). However pioglitazone combination therapy with metformin and alpha glycosidase inhibitors revealed lower weight gain: (0.31±0.2 kg) and (0.16±0.4 kg) respectively. Higher doses of pioglitazone were associated with more important weight gain.

Limitations of the study:

1. The study is an open-label prospective observational study and not a double blinded randomized controlled trial.

2. Long term changes in weight were not assessed, as the mean follow up period was only 6 months.

3. There were very few patients (only 28) on pioglitazone monotherapy.