Validation of HF-Bioelectrical Impedance Analysis versus Body Mass Index in Classifying Overweight and Obese Pakistani Adults.

Abstract

To determine the validity of hand-to-foot bioelectrical impedance analysis (HF-BIA) versus body mass index (BMI) to assess overweight and obesity status in adults against a reference method, dual-energy x-ray absorptiometry (DXA). It is a validation study conducted on 206 Pakistani adults ≥20 years recruited through convenience sampling technique at PNS Shifa Hospital and Jinnah Post Medical Centre, Karachi, Pakistan. HF-BIA showed better sensitivity of 90.1% and 100% specificity with no false positive, but 9% false negative as compared to BMI which indicated 80.3% sensitivity and 100% specificity with a false-negative rate of 19.6%.HF-BIA also showed better sensitivity 80.9-97.1% with 100% specificity and PPV across all age groups. The correlation coefficient between BMI and DXA bf% (r=0.67) was moderate and less than the correlation coefficient between HF-BIA and DXA bf % (r=0.87). Kappa agreement showed weak to a fair agreement between BMI and DXA bf % (0.1 overall; 0.22 men; 0.14 women) compared to HF-BIA, which had a better agreement between BIA bf% and DXA bf% (0.43 overall; 0.46 men; 0.34 women). HF-BIA bf % demonstrated a better discriminatory power than BMI (AUC of ≥0.91) and was better predictor of body fat than BMI. HF-BIA is a more accurate method than BMI and may be used consistently throughout the country in primary care and research to identify the fat-based overweight and obese in the Pakistani population.