Brazilian Registry of Thrombotic Thrombocytopenic Purpura: A prospective cohort study of diagnosis, management and outcomes in Brazil.

Most data supporting current knowledge about thrombotic thrombocytopenic purpura (TTP) come from high-income regions, while little is known about treatment access and prognosis in low- and middle-income countries. To address this gap, we conducted a multicenter prospective study that included 85 TTP patients in Brazil between 2018 and 2024, with a 12-month follow-up. The median age was 37 years (IQR 27-45) and 76% were female. The median PLASMIC score was six (IQR 6.0-7.0), and ADAMTS13 activity was tested in 62.4% of patients (all <10%). The median time from symptom onset to hospital admission was 8 days. Neurological manifestations were the most frequent (75.3%), followed by bleeding symptoms (58.8%) and abdominal pain (32.9%). Seventy-four patients (87.1%) underwent therapeutic plasma exchange (TPE), which was initiated within one day of admission (IQR 1-2). Corticosteroids were administered in 95.3% and rituximab in 56.5% of patients. Twenty-three patients (27.1%) required advanced life support and 13 (15.3%) died during hospitalization. In-hospital mortality was associated with older age and hemodynamic instability upon admission. Among survivors, 26% experienced exacerbation or relapse, and 22.4% developed chronic sequelae, mostly neurological and psychiatric symptoms. Rituximab use was protective against TTP relapses. In conclusion, TTP mortality in Brazil is higher than that observed in recent cohorts. TTP diagnosis and treatment in the country are delayed and outdated, negatively affecting disease prognosis. Ensuring rapid diagnosis and the availability of TPE and rituximab, a cost-effective treatment strategy, is essential for improving outcomes and reducing morbidity, including in low- and middle-income countries.