The aim of this study was to investigate the effect of hemodialysis on
body composition assessment by dual-energy x-ray absorptiometry (DEXA).
Seventeen patients with chronic renal failure who were on a regular
hemodialysis schedule were studied. Body weight and body composition
were assessed immediately before and approximately 1 hour after a
typical hemodialysis session. Body weight was assessed by means of an
electronic balance. Body composition measurements were made by DEXA.
Whole-body and subtotal (head and neck excluded) analysis assessed the
following parameters: body weight, bone mineral density (BMD), bone
mineral content (BMC), and fat (FTM)and lean (LTM) tissue mass. BMC,
FTM, and LTM were estimated separately for the trunk, arms, and legs.
The mean body weight reduction after hemodialysis was 2.8 +/- 1.1 kg
(mean +/- SD). Concerning whole-body analysis, no change was observed in
mean BMC and FTM after hemodialysis. On the contrary, a significant
reduction was observed in mean body weight as assessed by DEXA (before
hemodialysis, 65.0 +/- 11.4 kg; after, 62.2 +/- 10.9 kg, P=.0003), as
well as in mean LTM (before hemodialysis, 42.7 +/- 9.4 kg; after, 39.7
+/- 9.0 kg, P=.0003). Similar results were obtained from subtotal and
regional analysis. Body weight changes as measured by the electronic
balance exhibited a strong positive correlation with the changes in both
body weight and LTM as assessed by DEXA (r=.989, standard error of the
estimate [SEE]=0.167 kg and r=.941, SEE=0.382 kg, respectively,
P<.0001). It is concluded that gravimetric changes induced by
hemodialysis are highly correlated with LTM changes and are not
associated with changes in BMC or FTM estimated by DEXA. Copyright (C)
1997 by W.B. Saunders Company
