Abstract

Background/Objectives: Thrombotic microangiopathies are rare, life-threatening hematological disorders characterized by microangiopathic hemolytic anemia, thrombocytopenia, and end-organ injury. This study was conducted in a setting where ADAMTS13 activity testing became available only from 2015 onward and complement-targeted therapy (eculizumab) had limited accessibility throughout most of the study period, conditions that shaped both diagnostic classification and treatment outcomes. Their clinical presentation, treatment response, and prognosis vary according to etiology, making early recognition and subtype classification clinically important. This study aimed to evaluate the etiological distribution, clinical features, treatment responses, and outcomes of adult patients with thrombotic microangiopathy at a tertiary-center real-world cohort. Methods: This retrospective cohort study included 47 adult patients (≥18 years) hospitalized with thrombocytopenia and microangiopathic hemolytic anemia (MAHA) in a nine-year period. Patients were classified as thrombotic thrombocytopenic purpura (TTP), hemolytic uremic syndrome (HUS), or secondary TMA based on clinical and laboratory evaluation. Demographic characteristics, clinical manifestations, laboratory parameters, treatments, and outcomes were analyzed. Results: The mean age was 45.3 ± 15.2 years, and 72.3% of patients were female. Primary thrombotic microangiopathy accounted for 74.5% of cases, including thrombotic thrombocytopenic purpura in 53.2% and hemolytic uremic syndrome in 21.2%; secondary thrombotic microangiopathy accounted for 25.5%. Hemodialysis was required in all patients with hemolytic uremic syndrome compared with 16% of those with thrombotic thrombocytopenic purpura. The complete response rate was 74.5%, and in-hospital mortality was 25.5%. In multivariable Cox regression analysis, treatment non-response and reduced post-treatment estimated glomerular filtration rate independently predicted mortality. Conclusions: Adult TMAs are characterized by considerable etiological and clinical heterogeneity, which makes differential diagnosis challenging, particularly in settings where access to contemporary diagnostic tests and targeted treatments is limited. In this cohort, in the absence of ADAMTS13 testing, TTP was the most frequent subtype, while treatment non-response and renal impairment emerged as the main factors associated with mortality. These findings emphasize the need for early clinical recognition and careful subtype-based differential diagnosis, which will reduce morbidity and mortality by permitting rapid initiation of pathophysiology-based appropriate interventions, i.e., PEx, immune suppression and caplacizumab for immune TTP and anti-complement therapy for aHUS, and limiting the inappropriate use of PEx with its complications, including sepsis.

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