Receiver operating characteristics curve analysis of body fat & body mass index in dyslipidaemic Asian Indians

Background & objectives: Optimal limit of body mass index (BMI) for Asian Indians remains to be defined. In this study, we describe the anthropometric and lipid profiles and determine the appropriate cut-offs of BMI for defining obesity in dyslipidaemic patients. Methods: Correlations were carried out between lipid profile and anthropometric variables in 217 dyslipidaemic Asian Indians and the data were compared to those of 123 healthy historical controls. Receiver operating characteristics (ROC) curve analysis was carried out to determine the appropriate cut-offs of BMI for defining obesity taking the percentage of body fat (% BF) as the standard. Results: Dyslipidaemic patients had high waist-hip ratio (W-HR) and percentage of BF. The prevalence of obesity as measured by percentage of BF was significantly (P<0.05) higher as compared to obesity defined by the BMI cut-off. W-HR was the most important independent predictor (odds ratio: 2.8; 95% CI: 1.02-7.83) of atherogenic dyslipidaemia on multivariate logistic regression analysis. On ROC curve analysis the suggested appropriate cut-offs of BMI were; males 24.0 kg/m² (sensitivity, 74.7%, and specificity, 79.7%), and females 23.0 kg/m² (sensitivity, 85.7% and specificity, 62.5%). According to the suggested lower limits of BMI, an additional 15 per cent dyslipidaemic patients will be diagnosed as obese. Interpretation & conclusion: The observations in dyslipidaemic Asian Indians suggest high prevalence rates of generalized and abdominal obesity, and that high values of W-HR alone predisposes to atherogenic dyslipidaemia. Further, obesity may be optimally defined by a lower cut-off of BMI. The revised criteria for the BMI-based diagnosis of obesity will lead to a more rational management of dyslipidaemia in Asian Indians.