Bioelectrical impedance in young patients with cystic fibrosis: Validation of a specific equation and clinical relevance

• Published in: Journal of cystic fibrosis Vol. 15; no. 6; pp. 825 - 833
• Main Authors: Charatsi, A.M, Dusser, P, Freund, R, Maruani, G, Rossin, H, Boulier, A, Le Bourgeois, M, Chedevergne, F, de Blic, J, Letourneur, A, Casimir, G, Jais, J.P, Sermet-Gaudelus, I
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01-11-2016
• Subjects: Absorptiometry, Photon - methods; Adolescent; Bioelectrical impedance analysis; Body Composition; Body Mass Index; Child; Cystic fibrosis; Cystic Fibrosis - diagnosis; Cystic Fibrosis - physiopathology; Diaphragm; Electric Impedance; Fat-free mass; Female; France; Humans; Lung function; Male; Prognosis; Prospective Studies; Pulmonary/Respiratory; Respiratory Function Tests - methods; Statistics as Topic; Young Adult; forced vital capacity; Cl; impedance; FFM; maximal inspiratory pressure; forced residual capacity by helium dilution; body composition; bias; chloride; dual x-ray absorptiometry; phase angle; LOA; PI max; body mass index; FRC-He; IGF-1; non-invasive ventilation; IQR; DXA; resistance; Tanner stage; RE; FEV1; BC; reactance; limits of agreement; RV; FM; fat mass; BI; fat-free mass; TLC; pulmonary function test(s); interquartile range; Lung function; cystic fibrosis; X; PE max; bioelectrical impedance analysis; Z; BIA; BMI; residual volume; CF; PFT(s); maximal expiratory pressure; forced expiratory volume in 1 s; insulin growth factor-1; PA; FVC; total lung capacity; NIV; Diaphragm; TS; Fat-free mass; Body composition; Cystic fibrosis; Bioelectrical impedance analysis
• ISSN: 1569-1993; 1873-5010
• DOI: 10.1016/j.jcf.2016.05.004

Abstract Background Body composition (BC) analysis based on bioelectrical impedance analysis (BIA) provides conflicting results. The purpose of the study was to validate an equation specific for young patients with cystic fibrosis (CF), describe their BC and investigate its association with lung function. Methods Fifty-four young CF patients were evaluated by BIA and dual X-ray absorptiometry (DXA). An empirically derived CF-specific equation for fat-free mass (FFM) estimation by BIA was elaborated after stepwise multivariate regression and the agreement between BIA and DXA was assessed by Bland–Altman plots. The association between BC and lung function was investigated by regression analysis. Results The mean difference between the BIA and DXA assessment was close to zero. A total of 22.5% of patients ( n = 9) presented a FFM z -score ≤ − 2. They had a worse pulmonary function and diaphragmatic impairment. Among these 9 patients, 7 had a normal BMI z -score > − 1. Conclusions BIA, based on a CF-specific equation, is a reliable method for BC assessment and allows the identification of patients at risk of nutritional degradation and bad respiratory prognosis.