A prognostic model (BATAP) with external validation for patients with transplant-associated thrombotic microangiopathy.

Transplant-associated thrombotic microangiopathy (TA-TMA) is a potentially life-threatening complication following allogeneic hematopoietic stem cell transplantation (allo-HSCT). Information on markers for early prognostication remains limited, and no predictive tools for TA-TMA are available. We attempt to develop and validate a prognostic model for TA-TMA. A total of 507 patients who developed TA-TMA following allo-HSCT were retrospectively identified and separated into a derivation cohort and a validation cohort according to the time of transplantation to perform external temporal validation. Patient age (OR 2.371, 95% CI 1.264-4.445), anemia (OR 2.836, 95% CI 1.566-5.138), severe thrombocytopenia (OR 3.871, 95% CI 2.156-6.950), elevated total bilirubin (OR 2.716, 95% CI 1.489-4.955) and proteinuria (OR 2.289, 95% CI 1.257-4.168) were identified as independent prognostic factors for the 6-month outcome of TA-TMA. A risk score model termed BATAP (Bilirubin, Age, Thrombocytopenia, Anemia, Proteinuria) was then constructed according to the regression coefficients. The validated c-statistics were 0.816 (95% CI 0.766-0.867) and 0.756 (95% CI 0.696-0.817) in the internal and external validation, respectively. Calibration plots indicated that the model-predicted probabilities correlated well with the actual observed frequencies. This predictive model may facilitate the prognostication of TA-TMA and contribute to the early identification of high-risk patients.