Epidemiological and Clinical Characteristics of Atypical Hemolytic Uremic Syndrome in China

Background: Atypical hemolytic uremic syndrome (aHUS) is a rare thrombotic microangiopathic disease that can lead to acute renal failure and hemolysis. Nevertheless, there is lack of nationwide data in China. This study intended to review and summarize the epidemiological characteristics and outcome of aHUS in China. Methods: In this observational cohort study, we collected data from the Hospital Quality Monitoring System of China, a direct reporting system of medical data that covers abstract medical records from 5800 public hospitals in 31 provinces and municipalities from 2018 to 2022. All patients diagnosed with aHUS based on ICD-10 coding were enrolled. Patients missing unique identifier number or basic demographic information were excluded. Results: 372 unique aHUS patients were identified, 45.6% of whom were male. Age distribution showed double peaks: children and women at thirties (Figure 1). Prevalence rates varied greatly among provinces, with the top 5 provinces being Inner Mongolia, Chongqing, Xinjiang, Guangxi, and Xizang, four of which were minority autonomous regions. The incidence of aHUS increased from 0.038 (2018) to 2.996 per million hospital admission (2022). 81% of the patients were first diagnosed in tertiary hospitals, with an average length of stay of 17.6 days. The top five admitting departments were nephrology, intensive care unit, pediatrics, hematology and general internal medicine. 37.5% of patients received dialysis, 20.3% received plasma exchange, 5.1% of patients underwent renal biopsy. The proportion of plasma exchange increased from 14.3% (2018) to 25.8% (2022), while intensive care unit support increased from 9.5% (2019) to 29.6% (2022). The combined proportion of discharges against medical advices and in-hospital deaths dropped from 33.3% (2019) to 16.9% (2022). Conclusion: AHUS manifested with age and gender preference. With intensive support and treatment being increasing common, the proportion of adverse outcomes decreased through years in China. Funding: Government Support – Non-U.S.Figure 1.Age and sex distribution of aHUS patients.