Long-term outcome of diarrhea-associated hemolytic uremic syndrome is poorly related to markers of kidney injury at 1-year follow-up in a population-based cohort.

Background: Hemolytic uremic syndrome due to Shiga toxin-producing E. coli (STEC-HUS) is the main cause of acute kidney injury in young children. Most fully recover kidney function; however, some develop long-term sequelae. We aimed to determine whether kidney injury 1 year after HUS onset is associated with long-term kidney outcome in pediatric STEC-HUS.

Methods: A retrospective population-based study of children < 15 years with STEC-HUS between 1992 and 2012 was performed. Mixed effects logistic regression was used to investigate associations between kidney injury at 1 year and long-term kidney outcome.

Results: Ninety-eight STEC-HUS cases were reported. Of 96 patients who survived acute phase, 84 were evaluated at 1-year follow-up of whom 42 (44% of survivors) showed ≥ 1 signs of kidney injury. Data from 81 patients were collected after median follow-up of 8.7 (IQR 3.5-12.7) years. At last follow-up, 42 (44% of survivors) had ≥ 1 signs of kidney injury including decreased estimated glomerular filtration rate (eGFR) < 90 mL/min/1.73 m (n = 30), proteinuria (n = 17), or hypertension (n = 5). Among 42 patients with kidney injuries at 1-year follow-up, only 22 (52%) still had kidney disease at last follow-up. Conversely, of 33 patients without kidney injury at 1-year and available long-term outcome data, 11 (33%) had proteinuria or decreased GFR at last follow-up. There was no statistically significant association between kidney injury at 1 year and long-term kidney outcome.

Conclusions: Since kidney sequelae may appear at variable time intervals after acute HUS, all patients need lifelong follow-up to detect early signs of chronic kidney disease and propose measures to slow progression.