Characteristics and outcomes of children with primary oxalosis requiring renal replacement therapy

Abstract

Background and objectives: Primary hyperoxaluria (PH) as a cause of ESRD in children is believed to have poor outcomes. Data on management and outcomes of these children remain scarce.

Design, setting, participants, & measurements: This study included patients aged <19 years who started renal replacement therapy (RRT) between 1979 and 2009 from 31 countries providing data to a large European registry.

Results: Of 9247 incident patients receiving RRT, 100 patients had PH. PH children were significantly younger than non-PH children at the start of RRT. The median age at RRT of PH children decreased from 9.8 years in 1979-1989 to 1.5 years in 2000-2009. Survival was 86%, 79%, and 76% among PH patients at 1, 3, and 5 years after the start of RRT, compared with 97%, 94%, and 92% in non-PH patients, resulting in a three-fold increased risk of death over non-PH patients. PH and non-PH patient survival improved over time. Sixty-eight PH children received a first kidney (n=13) or liver-kidney transplantation (n=55). Although the comparison was hampered by the lower number of kidney transplantations primarily derived from the earlier era of RRT, kidney graft survival in PH patients was 82%, 79%, and 76% at 1, 3, and 5 years for liver-kidney transplantation and 46%, 28%, and 14% at 1, 3, and 5 years for kidney transplantation alone, compared with 95%, 90%, and 85% in non-PH patients.

Conclusions: The outcomes of PH children with ESRD are still poorer than in non-PH children but have substantially improved over time.

Figure 1.

Age at start of RRT in patients with primary hyperoxaluria according to RRT era. The horizontal line in the middle of the box represents the median, the bottom and top of the box represent the lower and upper quartiles, respectively, and the ends of the whiskers represent the minimum and the maximum. RRT, renal replacement therapy.

Figure 2.

Unadjusted 5-year survival on RRT for PH patients according to period of RRT versus non-PH patients (log-rank P<0.001). RRT, renal replacement therapy; PH, primary hyperoxaluria.

Figure 3.

Unadjusted 3-year survival on RRT in children aged <2 years for PH patients versus non-PH patients (log-rank P=0.03). RRT, renal replacement therapy; PH, primary hyperoxaluria.

Figure 4.

Unadjusted 5-year kidney graft survival for PH patients versus non-PH patients (log-rank P<0.001). PH, primary hyperoxaluria; KTx, kidney transplant; L-KTx, liver-kidney transplant; Tx, transplant.