Effect of Dialysis Dose on Nutritional Status of Children on Chronic Hemodialysis

Abstract

It had been suggested that larger hemodialysis (HD) doses in children could result in better appetite, higher protein intake, better nutritional status and better growth. We investigated how different HD doses affect protein intake and nutritional status of children on chronic HD. Indices of nutritional status used were normalized protein catabolic rate (nPCR) calculated by formal 3-sample urea kinetic modeling and serum albumin level. Data of 38 HD sessions in 15 stable patients (6 males, 9 females) aged 14.5 ± 3.28 years (mean ± SD) were analyzed. HD sessions were divided into three groups based on delivered Kt/V: group 1 (n = 5), inadequate (Kt/V < 1.3, mean 1.05 ± 0.14); group 2 (n = 12), adequate (Kt/V = 1.3–1.6, mean 1.50 ± 0.07) and group 3 (n = 21), high (Kt/V >1.6, mean 1.94 ± 0.22). Mean nPCR and Kt/V per patient during the studied week were estimated for 11 patients in whom 3 HD sessions were available within the 38 sessions analyzed. Serum albumin level was adequate in all patients (43.77 ± 2.28 g/l). Mean overall Kt/V and nPCR were 1.68 ± 0.36 and 1.26 ± 0.23, respectively, r = 0.430. Average nPCR differed between groups depending on Kt/V. It was lowest in group 1 (1.01 ± 0.12 g/kg/day) where the highest correlation between nPCR and Kt/V was found (r = 0.648). nPCR was higher and similar in groups 2 (1.27 ± 0.23 g/kg/day) and 3 (1.31 ± 0.22 g/kg/day), with low correlation coefficients between nPCR and Kt/V in both groups (r = 0.275 and r = 0.197, respectively). A weak positive correlation (r = 0.249) between nPCR and Kt/V was found when average weekly values per patient (n = 11) were analyzed. Results of groups 1 and 2 confirm, what is already well established in adults, that adequate dialysis needs to be achieved in order to insure good protein intake. However, our data clearly show that nPCR did not increase with a further increase in delivered HD dose, i.e. Kt/V >1.6. Our results show that the nutritional status of children on chronic HD does not seem to benefit from very high HD doses (Kt/V >1.6).

nPCR assessment and IDPN treatment of malnutrition in pediatric hemodialysis patients

“…Patient nutritional status was not related to the delivered dose of dialysis over the time course of study, since patients in both the pre-IDPN and IDPN periods received a mean spKt/V>1.4. We do not suggest that spKt/V>1.4 is an optimal or even adequate dose of dialysis, although one pediatric study reported improvement in nPCR and appetite in patients with spKt/V>1.3 compared with patients with spKt/V<1.3 [25]. Nevertheless, the current study demonstrates that hemodialysis patient outcome is dependent on more than just the amount of urea clearance during hemodialysis; delivery of optimal hemodialysis also requires assessment of nutritional status.…”

Nutritional Status in Children with Chronic Renal Failure on Hemodialysis

“…This study showed no significant correlation between height z-score and Kt/V. This is in accordance with studies stated that although adequate dialysis needs to be achieved in order to ensure good protein intake, high dialysis doses (< 1.6) are of no further benefit [30]. This, however, doesn't exclude the possibility that a Kt/V less than 1.2 would be associated with poor growth.…”

Growth and PTH in prepubertal children on long-term dialysis

“…We do not have individual data on all our patients, another deficiency of our study, but our aim is for a Kt/V of >1.6 per session for HD and >2.1 per week for PD. One study in children has shown improvement in growth with a better Kt/V [6,21], but there appears to be a ceiling above which no further benefit is seen [22].…”