Acquired thrombotic thrombocytopenic purpura (aTTP) is an ultra-rare, potentially life-threatening thrombotic microangiopathy (TMA). Data on epidemiology, disease management, and clinical outcomes are scarce and often heterogeneous. The aim of this study was to assess the epidemiology, disease management, and clinical outcomes in patients with aTTP in the United States.

This longitudinal retrospective observational study of the Optum-Humedica database included patients with aTTP diagnosis from October 2015 to December 2019 if they had ≥1 documented ADAMTS13 activity <10% or ≥1 aTTP episode (≥1 inpatient stay with TMA diagnosis and ≥1 therapeutic plasma exchange [TPE] during the same stay); patients with conditions that mimic aTTP were excluded. Patients were followed until loss to follow-up, end of study period, or death. All analyses were descriptive.

Among 666 patients with aTTP diagnosis, 302 (45%) had ≥1 aTTP episode. Annual incidence of ≥1 aTTP episode was 1.81/million (based on data from 2016–2019). Patients with ≥1 aTTP episode received a mean of 16.7 TPE sessions; 59% used rituximab. Among patients with ≥1 aTTP episode, exacerbations occurred in 17% (52/302); relapse occurred in 11% (34/302). Mortality rate was 25% (167/666) among all patients with aTTP diagnosis and 14% (41/302) among patients with ≥1 aTTP episode.

Despite treatment with TPE and immunosuppressants, the high mortality and morbidity observed in this patient population demonstrates the need for more effective therapies to improve clinical outcomes.