The Indian Diabetes Prevention Programme Shows That Lifestyle Modification and Metformin Prevent Type 2 Diabetes in Asian Indian Subjects With Impaired Glucose Tolerance (IDPP1)

Lifestyle modification helps in primary prevention of diabetes in multiethnic Americans, Finnish and Chinese populations. In a prospective community based study, we tested if the conversion to diabetes could be influenced by interventions in native Asian Indians with impaired glucose tolerance (IGT) who were younger, leaner and more insulin resistant than the above populations.

We randomized 531 (Men : Women, 421 : 110) subjects with IGT [mean age of 45.9 + 5.7 years and body mass index (BMI) of 25.8 + 3.5 kg/m2 into four groups. Group 1 was the control (CON), Group 2 was advised lifestyle modification (LSM), Group 3 was treated with metformin (MET) and Group 4 with LSM plus MET. Primary outcome measure was type 2 diabetes diagnosed by the WHO criteria.

In a median follow up of 30 months, three year cumulative incidence of diabetes were 55.0%, 39.3%, 40.5% and 39.5% in group 1 to 4 respectively. The relative risk reduction was 28.5% with LSM (95 % confidence interval (CI), (20.5 - 37.3), (p=0.018), 26.4% with MET (95% CI, 19.1 - 35.1) (p = 0.029) and 28.2% with LSM plus MET (95% CI, 20.3 - 37.0), (P=0.022) versus control group. The numbers needed to treat to prevent one incident case of diabetes were 6.4 for LSM, 6.9 for MET and 6.5 for LSM+MET.

Conversion of IGT to diabetes is high in native Asian Indians. LSM and metformin significantly reduced the incidence of diabetes in Asian Indians with IGT. There was no added benefit by combining both.