Peritoneal Loss of Growth Hormone in Children on Automated Peritoneal Dialysis

Abstract

Objective

To provide quantitative data regarding the daily dialytic loss of growth hormone (GH) in children on peritoneal dialysis (PD).

Design

Prospective study involving 24-hour dialysate collections on 3 consecutive days in patients with and without recombinant human GH (rhGH) treatment.

Setting

Single-center outpatient PD program.

Patients

Twenty-six children undergoing automated PD (APD): 6 with and 20 without daily rhGH.

Main Outcome Measures

Daily peritoneal losses of GH, α₁-, β₂-microglobulin, transferrin, and albumin.

Results

The mean (±SEM) daily dialytic GH loss was 2.18 ± 0.62 μg/1.73 m² per day in rhGH-treated patients and 0.42 ± 0.28 μg/1.73 m² per day in untreated patients, (p < 0.05). The intraindividual coefficient of variation of daily GH loss was 65%. The peritoneal loss of GH was positively correlated with that of β₂-microglobulin (r = 0.77, p < 0.001) and α₁-microglobulin (r = 0.51, p < 0.01). The variability in β₂-microglobulin and α₁-microglobulin elimination, together with the use of rhGH, explained 66% of the total variability of daily GH excretion. In patients without rhGH therapy, the daily peritoneal GH loss was approximately 0.05% of the estimated daily endogenous production rate based on previous estimates in children with end-stage renal failure. In patients on rhGH therapy, less than 0.1% of the injected rhGH dose was eliminated by dialysis.

Conclusion

Peritoneal losses of GH in children on APD account only for a minute fraction of endogenous metabolic clearance, and do not explain the variability of the rhGH treatment response. The assessment of dialytic GH elimination may be used to estimate time-integrated mean plasma GH concentrations, and to monitor rhGH treatment compliance.