# Haemolytic uremic syndrome as a cause of chronic kidney disease stage 5 in children is in retreat: results from the Polish Registry of Kidney Replacement Therapy in children (2000–2023)

## TL;DR

Haemolytic uremic syndrome is becoming a rarer cause of severe kidney disease in children, with better outcomes due to improved treatments.

## Contribution

The study shows a decline in HUS-related chronic kidney disease in children and improved survival with modern therapies.

## Key findings

- CM-HUS and STEC-HUS are increasingly rare causes of CKD5 in children.
- Children with STEC-HUS had better survival and graft outcomes than those with CM-HUS.
- CM-HUS cases developed CKD5 significantly earlier than STEC-HUS cases.

## Abstract

Haemolytic uremic syndrome (HUS) is a life-threatening disease with a historically poor prognosis in children receiving maintenance kidney replacement therapy (KRT). This study aimed to analyse the incidence and outcome of chronic kidney disease stage 5 (CKD5) due to Escherichia coli-HUS (STEC-HUS) and complement-mediated HUS (CM-HUS) in children, compared with controls with non-HUS CKD5 over the last 24 years.

The study included 1488 children undergoing KRT in Poland between 2000 and 2023. Thirty-nine patients with CM-HUS and 18 with STEC-HUS were identified and analysed for incidence, KRT modality and survival.

The incidence rate of CKD5 was 0.09 cases/million age-related population (marp) for STEC-HUS and 0.23/marp for CM-HUS, while no new cases have been observed in recent years. CKD5 due to CM-HUS developed significantly earlier from initial HUS manifestation than in STEC-HUS (median 0.2 vs. 9.8 years). CM-HUS was associated with younger age at initiation of KRT compared to STEC-HUS and non-HUS controls (median 6.0 years vs. 10.9 and 10.9 years), with higher risk of death (Hazard Ratio 1.92, 95% confidence interval 0.9–4.13) and worse 5-year kidney graft survival at 77%, 93% and 90%, respectively (p < 0.001).

In recent years, both CM-HUS and STEC-HUS have become increasingly rare causes of CKD5 in children. CKD5 due to CM-HUS in the eculizumab era and due to STEC-HUS after improving supportive treatment is exceptional. Children on KRT due to STEC-HUS had a significantly better survival, shorter waiting time for kidney transplantation and better kidney graft survival compared to the CM-HUS group.

A higher resolution version of the Graphical abstract is available as Supplementary information.

A higher resolution version of the Graphical abstract is available as Supplementary information.

The online version contains supplementary material available at 10.1007/s00467-024-06584-2.