In Vivo Precision of the GE iDXA for the Assessment of Total Body Composition and Fat Distribution in Severely Obese Patients

Objective: To evaluate the precision of the iDXA for total body composition and fat distribution measurements in severely obese patients. Design and Methods: Sixty-five severely obese participants with a mean age of 46 +/- 11 years, BMI of 49 +/- 6 kg/m(2), and a mean body mass of 137.3 +/- 20.9 kg took part in this investigation. Two consecutive iDXA scans with repositioning of the total body were conducted for each participant. The coefficient of variation (CV), the root-mean-square (RMS) averages of standard deviations of repeated measurements, the corresponding 95% least significant change, and Intraclass Correlations (ICC) were calculated. Results: Precision expressed as % CV, for total body bone mineral content, fat free mass, total body fat, total body lean, and % total body fat were 1.08%, 0.94%, 0.90%, 1.00%, 0.79%, respectively. Precision was 1.44% for gynoid fat distribution and 1.64% for android fat (AF) distribution. The ICCs in all DXA measurements were 0.99 with % AF having the lowest at 0.96. Conclusions: The GE Lunar iDXA (TM) demonstrated excellent precision for total body composition assessments and is the first study to assess reproducibility in severely obese individuals.