Bioelectrical impedance analysis (BIA) and physical fitness in patients with idiopathic pulmonary fibrosis (IPF)

Body composition and physical fitness (PF) are major components of nutritional status which may be evaluated in the clinical setting using bioelectrical impedance analysis (BIA) and different specific tests, respectively. As raw BIA variables, multifrequency ratio (IR2505) between impedance=Z at 250 kHz and Z at 5 kHz, and phase angle (PhA at 50 kHz) were considered as indices of both body cell mass and the ratio extra/intracellular water (i.e. muscle quality). Aim: To evaluate the relationships between PF and raw BIA variables in IPF patients. Materials and Methods: Ninety-eight IPF patients took part in the study. Body composition was determined on the whole body with BIA (HUMAN IM-TOUCH, DS Medica). As PF tests, handgrip strength (HGS) was performed for assessing muscle strength, and gait speed=GS, chair stand test=CST, and timed up and go test=TUG for evaluating physical performance. Results: Mean age of the IPF patients was 69.2±7.4 yrs. IR2505 and PhA were altered compared to reference values, more frequently in advanced stages of disease. HGS significantly correlated with age, weight and body composition, whereas TUG was associated with age and stature. There were moderate correlations of PF variables with IR2505 and PhA. Multiple linear regression indicated that IR2505 or PhA remained independent predictors of PF even after taken into consideration stature, weight or body composition. Conclusions: The preliminary results of the study suggest that in IPF patients there is a significant association or HGS or physical performance tests with raw BIA variables such as multifrequency ratio or phase angle.