Results of long-term follow-up in patients cohort with atypical hemolytic-uremic syndrome

Introduction. Atypical hemolytic uremic syndrome (aHUS) is a rare form of thrombotic microangiopathy (TMA) associated with dysregulation of the complement system. aHUS take an important place in the spectrum of kidney disease because of the high risk of kidney loss and damage to other vital organs.

Objective. The evaluate the outcomes of follow-up and treatment of patients with aHUS receiving complement-blocking therapy (CBT), with assessment of overall and renal survival.

Materials and methods. Medical records and outpatient charts of 25 patients with aHUS followed at the nephrology department of Yekaterinburg Regional Clinical Hospital No. 1 between 2014 and 2024 (10 years) were analyzed. Differential diagnostic methods, as well as morphological (kidney biopsy) and genetic studies (genetic testing of the complement system) studies, were performed. Treatment included plasma therapy (fresh frozen plasma (FFP) transfusions and/or plasma exchange) and/or CBT with eculizumab.

Statistical analysis was performed using SPSS version 24. Descriptive statistics, Kaplan-Meier survival estimates with corresponding graphs, and Fisher's exact test for intergroup comparisons were used.

Results. The identified triggers of aHUS included pregnancy and childbirth (32%), infections (16%), IgA nephropathy (8%), oral contraceptive use (8%), paint inhalation poisoning (4%), and kidney transplantation (4%). Genetic testing of the complement system was performed in 22 patients, and pathogenic variants associated with aHUS were identified in 12 (54.5%) of the examined patients. Overall patient survival rates were 96% at as: 1 year, and 89% at both 5 and 10 years. Renal survival was 100% at 1 year and 84% at 5years. Plasma therapy with FFP transfusions was administrated to 10 (40%) patients, and plasma exchange was performed in 16 (64%) patients. Specific CBT with eculizumab was used in 22 (88%) patients. Discontinuation of eculizumab was associated with a high risk of TMA recurrence (36%).

Conclusion. Long-term follow-up of 25 patients with aHUS receiving specific CBT demonstrated satisfactory overall patient survival (96% at 1 year, 89% at 5 years) and renal survival (100% at 1year, and 84% 5 years).

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