Association between muscle hydration measures acquired using bioelectrical impedance spectroscopy and magnetic resonance imaging in healthy and hemodialysis population

Abstract

Establishing the effect of fluctuating extracellular fluid (ECF) volume on muscle strength in people with end‐stage renal disease (ESRD) on hemodialysis (HD) is essential, as inadequate hydration of the skeletal muscles impacts its strength and endurance. Bioelectrical impedance spectroscopy (BIS) has been a widely used method for estimating ECF volume of a limb or calf segment. Magnetic resonance imaging (MRI)‐acquired transverse relaxation times (T2) has also been used for estimating ECF volumes of individual skeletal muscles. The purpose of this study was to determine the association between T2 (gold standard) of tibialis anterior (TA), medial (MG), and lateral gastrocnemius (LG), and soleus muscles and calf BIS ECF, in healthy and in people with ESRD/HD. Calf BIS and MRI measures were collected on two occasions before and after HD session in people with ESRD/HD and on a single occasion for the healthy participants. Linear regression analysis was used to establish the association between these measures. Thirty‐two healthy and 22 participants on HD were recruited. The association between T2 of TA, LG, MG, and soleus muscles and ratio of calf BIS‐acquired ECF and intracellular fluids (ICF) were: TA: β = 0.30, P > 0.05; LG: β = 0.37, P = 0.035; MG: β = 0.43, P = 0.014; soleus: β = 0.60, P < 0.001. For the HD group, calf ECF was significantly associated with T2 of TA (β = 0.44, P = 0.042), and medial gastrocnemius (β = 0.47, P = 0.027) following HD only. Hence BIS‐acquired measures cannot be used to measure ECF volumes of a single muscle in the ESRD/HD population; however, BIS could be utilized to estimate ratio of ECF: ICF in healthy population for the LG, MG, and soleus muscles.

Sarcopenia and its individual criteria are associated, in part, with mortality among patients on hemodialysis

“…25 In addition, there is evidence that the hydration of muscle varies across the dialysis cycle, at least in the calf muscles. 26 Such variation would add variability to measures of muscle mass by all techniques, but perhaps more by BIS than others, and likely contributes to the difficulty of applying a particular threshold of muscle mass in defining sarcopenia in the dialysis population. Perhaps for these reasons, we were not able to identify alternative optimal cutpoints to define levels of atrophy associated with higher mortality by any indexing method.…”

Differences in the prevalence of sarcopenia in haemodialysis patients: the effects of gender and ethnicity

“…Previous studies have noted, particularly for haemodialysis patients, that the relationship between muscle strength and mass has been weak . However, the water content is increased prior to dialysis because muscle contains a relatively high amount of water and this then decreases post‐dialysis . Accordingly, measurements made post‐dialysis when patients are at a less over‐hydrated state are more representative of muscle mass and so we measured appendicular lean mass post‐dialysis .…”

The prevalence of muscle wasting (sarcopenia) in peritoneal dialysis patients varies with ethnicity due to differences in muscle mass measured by bioimpedance

“…during a dialysis session, and changes in hydration lead to differences in the estimation of muscle mass by magnetic resonance imaging, DXA and bioimpedance [21,22,23]. To exclude such confounding, we excluded patients with clinical signs of hypervolaemia.…”