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

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.