Albuminuria and Estimated GFR 5 Years After Escherichia coli O157 Hemolytic Uremic Syndrome: An Update

Background: Knowledge of the long-term prognosis of patients with diarrhea-associated hemolytic uremic syndrome (HUS) is important for patient counseling and follow-up. Estimates in the literature are highly variable, and previous studies did not use a healthy control group to establish outcomes attributable to HUS. Study Design: Prospective cohort study. Setting & Participants: 19 children who recovered from HUS after contamination of their municipal water supply by Escherichia coli O157:H7. Predictor: Outcomes of children who recovered from HUS were compared with a control group of 64 children who were healthy at the time of the outbreak. Both groups were similar in their demographics and follow-up testing. Outcomes & Measurements: Proteinuria, blood pressure, glomerular filtration rate (GFR) estimated by using serum creatinine or cystatin C level, and biochemical measures 5 years after the outbreak. Results: More children who recovered from HUS showed microalbuminuria than controls (20% versus 3%; relative risk, 6.0; 95% confidence interval, 1.1 to 32.8). There were no differences between groups in blood pressure or GFR when estimated by using serum creatinine level. GFR estimated by using cystatin C level was lower after HUS compared with controls (100 versus 110 mL/min/1.73 m²; P = 0.02), but no child had a GFR less than 80 mL/min/1.73 m². Other results, including fasting glucose, albumin, and C-reactive protein levels, did not differ between groups. Limitations: Although the homogenous nature of this outbreak is a strength, long-term results may generalize less well to patients with other strains of toxigenic E coli or in other settings. Conclusions: The prognosis of patients with HUS in this cohort was better than in other studies. Ongoing follow-up will clarify the clinical relevance of microalbuminuria and mild decreases in GFR 5 years after HUS recovery.