Multi-frequency bioelectrical impedance analysis for assessing fat mass and fat-free mass in stroke or transient ischaemic attack patients

Background/Objectives: Dual energy X-ray absorptiometry (DEXA) is considered as the reference method in assessing fat-free and fat mass but is costly and not a pragmatic option in daily clinical practice. If devices based on multi-frequency bioelectrical impedance analysis (MF-BIA), which are cheaper and portable, are valid and reliable in measuring body composition, these could be used in routine clinical practice in nutritional management of patients and populations where malnutrition is prevalent. Subjects/Methods: A study of MF-BIA against DEXA in assessing fat-free and fat mass, and two internal validation studies of MF-BIA were conducted. Bland & Altman analysis to assess comparison against DEXA and Cronbach’s α for internal validity were carried out. Results: Ten participants (mean age 66 years; 70% men) with a recent stroke or transient ischaemic attack (TIA) were recruited to assess against DEXA and the first internal validation. The second internal validation was based on 80 pairs of MF-BIA measurements in 40 stroke patients (mean age 70.3 years; 55% men) assessed at hospital admission and on discharge. There was a strong correlation between MF-BIA and DEXA (correlation coefficient was 0.88 for fat-free mass and 0.77 for fat mass). According to Bland & Altman analysis, MF-BIA and DEXA fat-free and fat mass estimates were similar. Internal consistency was high with Cronbach’s-α >0.9. Conclusion: MF-BIA can be reliably used in stroke and TIA patients. The feasibility, clinical and cost effectiveness of MF-BIA in routine monitoring and management of malnutrition in stroke and TIA patients with high prevalence of nutritional deficits is worthy of further evaluation.