Metabolic Profile of Persons with Newly Diagnosed Diabetes Using either Glycoslated Haemoglobin or Oral Glucose Tolerance Test in Primary Prevention Trials in Asian Indians

Background: To compare cardio metabolic characteristics of Asian Indians with incident type 2 diabetes diagnosed by Oral Glucose Tolerance Test (OGTT) or by Glycosylated Haemoglobin (HbA1c). Research Design and Methods: Data from two Indian Diabetes Prevention Studies in persons with Impaired Glucose Tolerance (IGT) was used. In 314 persons, diabetes was diagnosed by OGTT and another 67 persons had only HbA1c values ≥ 6.5% (≥48 mmol/mol). Cardiometabolic characteristics were compared in 3 sub-groups-1: Persons with positive OGTT only (HbA1c<6.5% (<48 mmol/mol) (n=125), 2: Persons with positive HbA1c but negative OGTT (n=67), 3: Those with both HbA1c and OGTT positive (n=189). Results: Diagnostic sensitivity of HbA1c was 67.2% when compared with OGTT criteria. Prevalence of obesity, abdominal obesity, hypertension, insulin resistance and lipid abnormalities were similar in all groups. Persons in groups-1 and 2 had similar metabolic characteristics, but for higher plasma glucose in the former group and higher HbA1c in the latter group. Prevalence of abnormalities was similar in both groups. Group with both the tests positive, had higher levels of insulin resistance. Conclusion: Metabolic characteristics of incident diabetic cases identified either by OGTT or by HbA1c were similar, except for a higher prevalence of insulin resistance among those who had both tests positive.