Body Weight and Muscle Thickness Changes after Hemodialysis: A Pilot Study with Bayesian Approach

Maintaining adequate body water balance is one aim of hemodialysis that is obtained by changing the blood volume. However, it is known that volume withdrawal is followed by water redistribution between extra- and intra-cellular spaces. In this context, the skeletal muscle tissue represents almost 50% of the total body mass, and like other soft tissues, consists of about 70%-80% water. Body weight is the main parameter used to monitor the body water change after a hemodialysis session, but it does not allow inferring about the water redistribution between extra and intracellular spaces. Thus, the present study aimed to assess the immediate impact of hemodialysis on body weight and the thickness of the rectus femoris muscle. Fifteen male patients with end-stage renal disease took part in the study. Muscle thickness, measured with ultrasound imaging, and body weight and were measured before (Pre) and after (Post) (within 5 to 10 minutes after) an hemodialysis session. Paired t-test was used to compare Pre and Post measures, and Bayesian analysis was applied to check the probability to replicate the same results (ie, the magnitude of the evidence). Our results indicated that body weight, but not rectus femoris muscle thickness, is significantly reduced immediately after hemodialysis. The rectus femoris muscle thickness seems not to be a reliable parameter to infer water redistribution after hemodialysis session.