Validation of Segmental Bioelectrical Impedance Analysis Compared with Dual Energy X-Ray Absorptiometry to Measure Body Composition in Patients with Obesity-related Heart Failure with Preserved Ejection Fraction

BackgroundAppendicular lean mass index (ALMI), a term used to describe appendicular lean soft tissue measured by dual-energy X-ray absorptiometry (DXA), is a major determinant of cardiorespiratory fitness in patients with obesity-related heart failure with preserved ejection fraction (HFpEF). Moreover, ALMI can be used to diagnose sarcopenia and sarcopenic obesity in this population. DXA is a reference standard for assessing body composition, however, segmental single-frequency bioelectrical impedance analysis (SF-BIA) could offer a more accessible, portable, cost-effective, and radiation-free alternative. To validate segmental SF-BIA for body composition analysis in patients with HFpEF and obesity, with a focus on ALMI. MethodsWe analyzed 62 consecutive euvolemic patients with persistent obesity-related HFpEF (83.8% female, 60.8{+/-} 2.8 years of age). We used both DXA and segmental SF-BIA to measure ALMI and appendicular fat mass index (AFMI), fat mass (FM), fat-free mass (FFM) in kg and as % of body weight, FM index, and FFM index. Correlations were assessed using Pearsons coefficients and Bland-Altman plots, while linear regression was performed to evaluate proportional bias. ResultsStrong, statistically significant correlations were found between BIA and DXA for ALMI (r=0.897), AFMI (r=0.864), FM (r=0.968), FM% (r=0.867), FFM (r=0.954), and FFM% (r=0.852), FM index (r=0.97), and FFM index (r=0.88) (all p<0.001). The Bland-Altman analysis demonstrated agreement between methods and linear regression indicated no significant proportional bias for all parameters, except for AFMI. ConclusionsSegmental SF-BIA-measured body composition shows strong correlations, appropriate agreements, and no proportional bias compared to DXA. Considering the central role of body composition and particularly of ALMI in patients with obesity-related HFpEF, when DXA is not readily available or contraindicated, segmental SF-BIA should be considered in this population.