Prevalence of insulin resistance in first degree relatives of type-2 diabetes mellitus patients: A prospective study in north Indian population.

A total of 172 first degree relatives (FDRs) and 178 controls were included in this study. All the cases and controls were subjected to various anthropometric measurements, fasting and postprandial glucose estimation, fasting insulin measurement and fasting lipid profile. Results revealed the prevalence of Impaired Fasting Glucose (IFG) (cases 37% Vs controls 11.6%), Impaired Glucose Tolerance (IGT) (cases 34.3% Vs controls 11.2%) and diabetes (cases 11.05% controls 3.37%) was significantly higher in first degree relatives. Insulin resistance was measured using various methods, which included fasting plasma insulin (FPI), Homeostasis Model Assessment for Insulin Resistance (HOMA(IR)), insulin sensitivity index (ISI) (Mffm/l). Prevalence of insulin resistance (Insulin Resistance) as observed comparing FPI and HOMA(IR) in cases and controls was 43.6% and 11.24% (P=0.005) and 37.8% and 12.47% (P=0.000) respectively. Prevalence of IR (Insulin Resistance) observed in cases having Normal Glucose Tolerance (NGT), Impaired Fasting Glucose (IFG), Impaired Glucose Tolerance (IGT) and diabetes mellitus measuring FPI Vs HOMA(IR) was 37.5% vs 30.2%, 45% vs 40%, 38.98% vs 37.28% and 36.84% vs 31.57% as accordingly. However, ISI (Mffm/l) was not found to be a promising index for IR due to its poor specificity. Though HOMA is taken as gold standard for measurement of IR globally, our study observed fasting plasma insulin representing high sensitivity (89.7%) and specificity (93.3%) as compared to HOMA. Thus FPI had emerged in this work as a simple and reliable test for diagnosing insulin resistance across the population susceptible to develop diabetes including FDRs.