Validity of bioelectric impedance analysis for body composition assessment in interstitial lung disease patients

Background: changes in body composition (BC) are common in interstitial lung disease, which leads to an increased risk of complications and infections, and are associated with poor quality of life and worse outcomes. BC assessment is important to identify malnutrition and sarcopenia. However, gold-standard techniques are not available in all clinical settings. Aims: this study aimed to evaluate the agreement and reliability of body composition estimated by bioelectric impedance analysis (BIA) and measured using dual-energy X-ray absorptiometry (DEXA) in women with interstitial lung disease. Methods: this is a cross-sectional study. BC (fat mass and appendicular skeletal muscle mass) were assessed using BIA multifrequency and DEXA in standardized conditions. Agreement and reliability between techniques were evaluated using Bland-Altman plots and the intraclass correlation coefficient (ICC). Results: a total of 50 women were evaluated. No differences were observed for FM (BIA, 25.8 ± 10.2 kg and DEXA, 26.3 ± 10.0 kg, p = 0.77) and ASMM (BIA, 14.1 ± 2.7 kg and DEXA, 13.9 ± 2.3 kg, p = 0.83). Based on ICC, good reliability was observed for FM (ICC, 0.98) and ASMM (ICC, 0.93). Conclusion: BC estimated by BIA showed good agreement and reliability with DEXA measurements. In the absence of this method, BIA can replace the DEXA technique for body composition assessment.