Metabolic syndrome does not increase the risk of conversion of impaired glucose tolerance to diabetes in Asian Indians--Result of Indian diabetes prevention programme

Abstract

Aims: In this study, we assessed for the prevalence of metabolic syndrome (MetS) in the cohort of subjects with impaired glucose tolerance (IGT) in the Indian Diabetes Prevention Programme and studied whether the syndrome enhanced the conversion to diabetes.

Methods: Effectiveness of lifestyle modification (LSM), metformin (Met) and LSM plus Met was tested in a randomised, controlled primary prevention study in subjects with IGT n=502 (M:W 397:105) at a median follow up of 30 months. Baseline prevalence of MetS was calculated using the WHO criteria. Insulin resistance (IR) was calculated using homeostasis model assessment (HOMA) method.

Results: MetS was present in 233 subjects (46.4%; 95% CI 41.9-50.9) in the total group, in men (n=168; 42.3%; 95% CI 37.4-47.3) and in women (n=65; 61.9%; 95% CI 51.9-71.2) (men versus women chi(2)=12.8, p=0.0005). Insulin resistance (HOMA-IR>or=4.1) was present in 69.1% with no gender difference. IR increased proportionately with increasing number of abnormalities, in IGT (39.8%), IGT plus one abnormality (56.5%) and IGT plus any two or more abnormalities (69.1%) (Mantel Haenszel chi(2)=22.8, p<0.0001). Incidence of diabetes was similar in subjects with (40.3%) (n=94/233) or without (40.1%) (n=108/269) MetS (p=0.97). Cox's regression analysis confirmed that MetS did not enhance the conversion rate of IGT to diabetes both in the control (HR=0.88, 95% CI 0.53-1.47, p=0.63) and in the total group (HR=1.02, 95% CI 0.78-1.35, p=0.88), after correcting for effects of intervention.

Conclusion: Prevalence of MetS is high in Asian Indian IGT subjects, especially in women. However, it did not influence the rate of conversion of IGT to diabetes.