Natural History of Type 2 Diabetes in Indians: Time to Progression
K.M. Venkat Narayan, Dimple Kondal, Howard H. Chang, Mohan Deepa, Unjali P. Gujral, Ranjit Mohan Anjana, Lisa R. Staimez, Shivani A. Patel, Mohammed K. Ali, Dorairaj Prabhakaran, Nikhil Tandon, Viswanathan Mohan
Abstract
OBJECTIVE: To describe the natural history of diabetes in Indians. RESEARCH DESIGN AND METHODS: Data are from participants older than 20 years in the Centre for Cardiometabolic Risk Reduction in South Asia longitudinal study. Glycemic states were defined per American Diabetes Association criteria. Markov models were used to estimate annual transition probabilities and sojourn time through states. RESULTS: Among 2,714 diabetes-free participants, 641 had isolated impaired fasting glucose (iIFG), and 341 had impaired glucose tolerance (IGT). The annual transition to diabetes for those with IGT was 13.9% (95% CI 12.0, 15.9) versus 8.6% (7.3, 9.8) for iIFG. In the normoglycemia ↔ iIFG → diabetes model, mean sojourn time in normoglycemia was 40.3 (34.6, 48.2) years, and sojourn time in iIFG was 9.7 (8.4, 11.4) years. For the normoglycemia ↔ IGT → diabetes model, mean sojourn time in normoglycemia was 34.5 (29.5, 40.8) years, and sojourn time in IGT was 6.1 (5.3, 7.1) years. CONCLUSIONS: Individuals reside in normoglycemia for 35-40 years; however, progression from prediabetes to diabetes is rapid.