Is Growth a Valid Outcome Measure of Dialysis Clearance in Children Undergoing Peritoneal Dialysis?

Abstract

♦ Objective

Our study evaluated growth as a clinical outcome measure of peritoneal dialysis (PD) adequacy in children with end-stage renal disease (ESRD).

♦ Design

This retrospective single-center study was carried out in our tertiary-care medical center.

♦ Patients

The study enrolled 24 patients who initiated dialysis after January 1, 1995, and who had been on dialysis for a minimum of 1 year.

♦ Results

The weekly mean total [PD + residual renal function (RRF)] creatinine clearance (C_Cr) and Kt/V_urea were 70.3 ± 18 L per 1.73 m² and 3.45 ± 0.73, respectively. Of the 24 patients, 12 (50%) were anuric. The mean height standard deviation score (SDS) changed to –1.78 at the end of 1 year from –1.58 at baseline. Catch-up growth (positive Δ height SDS) was observed in 9 patients (37%), 7 of whom (78%) had residual renal function (RRF). In contrast, only 5 of 15 patients (33%) with a negative ΔSDS for height had RRF (p < 0.025). The mean height SDS in patients with RRF improved to –1.64 from –1.78; in patients without RRF, it worsened to –1.90 from –1.37 (p = 0.01). While the weekly total Kt/V_urea in patients with RRF (3.53) was similar to that in patients without RRF (3.37, p = 0.6), only the native Kt/V_urea had a significant (but weak) positive correlation with Δheight SDS (r ² = 0.17, p = 0.04). In contrast, the total weekly C_Cr was significantly higher (p = 0.001) in patients with RRF (81.1 L/1.73 m²) as compared with those without RRF (59.5 L/1.73 m²). However, only the native C_Cr—and not the dialysis C_Cr—had a significant (but weak) positive correlation with Δheight SDS (r ² = 0.17, p = 0.04).

♦ Conclusions

These preliminary data provide evidence for a correlation between solute clearance and growth, with RRF exerting a significant influence on that outcome. The Kt/V_urea data also appear to contradict the presumed equivalence of PD and native clearance in children with ESRD.