Analysis of causes and outcomes of principal secondary thrombotic microangiopathy: a 9-year cohort study from a tertiary pediatric center in China.

BACKGROUND

Few large-scale cohort studies have reviewed consecutive cases of thrombotic microangiopathy (TMA), especially in children.

OBJECTIVES

The aim of our study was to evaluate causes and outcomes of TMA at a tertiary pediatric center in China over a 9-year period.

METHODS

We retrospectively analyzed consecutive pediatric TMA patients admitted to Beijing Children's Hospital from December 2015 to January 2025. The primary endpoint was death or progression to kidney failure. Multivariable Cox regression identified independent predictors of this composite endpoint.

RESULTS

We retrospectively analyzed 303 consecutive pediatric patients with a first episode of TMA. Secondary TMA was the most common type (n = 172; 57%), followed by atypical hemolytic uremic syndrome (n = 93; 31%), thrombotic thrombocytopenic purpura (n = 24; 8%), and Shiga toxin-producing Escherichia coli-associated hemolytic uremic syndrome (n = 14; 5%). Among the 172 cases of secondary TMA, the most common causes were hematopoietic stem cell transplantation (n = 95; 55%) and systemic diseases (n = 40; 23%). After a median follow-up of 35 months, death or kidney failure occurred in 53 (31%), 7 (8%), 1 (4%), and 0 patients with secondary TMA, atypical hemolytic uremic syndrome, thrombotic thrombocytopenic purpura, and Shiga toxin-producing Escherichia coli-associated hemolytic uremic syndrome, respectively. Multivariate Cox regression showed that secondary TMA (hazard ratio [HR], 3.57; 95% CI, 1.53-8.30; P < .01), the presence of heart failure and/or shock at onset (HR, 2.21; 95% CI, 1.24-3.93; P = .01), and the need for mechanical ventilation support due to respiratory failure (HR, 3.88; 95% CI, 2.19-6.88; P < .001) were independent risk factors for death or kidney failure.

CONCLUSION

This study shows that secondary TMA is the predominant form of pediatric TMA. Secondary TMA, heart failure/shock, and the requirement for mechanical ventilation were identified as independent risk factors for death or kidney failure in children.