Evaluation of surrogate markers for insulin resistance for defining metabolic syndrome in urban Indian adolescents

Abstract

Objective: To compare parameters of insulin resistance, with special reference to McAuley index, in urban Indian adolescents and to establish their cut-off values for defining metabolic syndrome. Design: Cross-sectional study. Setting: Schools located in four different geographical zones of Delhi, India. Participants: 695 apparently healthy adolescents grouped as normal weight (298), overweight (205) and obese (192). Outcome Measures: Cut-off point for indices of insulin resistance was assessed by fasting insulin, insulin glucose ratio, and other methods (HOMA model, QUICKI, McAuley index) to define metabolic syndrome. Results: The McAuley index increased progressively from normal weight to obese adolescents in both sexes. McAuley index was significantly lower in adolescents with metabolic syndrome (5.36 ± 1.28 vs. 7.05 ± 1.88; P<0.001). McAuley index had the highest area under curve of receiver operator characteristics [0.82 (0.02)] as compared to other indices of insulin resistance. McAuley index of 6.23 had the highest specificity (88%) with sensitivity of 63.3% for diagnosing metabolic syndrome, whereas insulin glucose ratio had the highest sensitivity (79.7%) but low (55.5%) specificity. McAuley index was negatively correlated with height (r= −0.257, P=<0.001), weight (r= −0.537, P=<0.001), body mass index (r= −0.579, P<0.001), waist circumference (r= −0.542, p<0.001), and waist hip ratio (r= −0.268, P<0.001). Conclusions: Among various parameters of insulin resistance, McAuley index had the highest specificity, and insulin glucose ratio had the highest sensitivity in diagnosing metabolic syndrome in urban Indian adolescents.