Validation of Drum Tower Severity Scoring (DTSS) System for Pyrrolizidine Alkaloid‐Induced Hepatic Sinusoidal Obstruction Syndrome

ABSTRACT Objectives The Drum Tower Severity Scoring (DTSS) system is a novel tool designed for assessing the outcome of anticoagulation therapy and disease severity in patients with pyrrolizidine alkaloid‐induced hepatic sinusoidal obstruction syndrome (PA‐HSOS). The aim of this study was to validate the predictive performance of the DTSS system in PA‐HSOS patient outcome. Methods We conducted a retrospective analysis of 111 PA‐HSOS patients who received standard anticoagulation–transjugular intrahepatic portosystemic shunt (TIPS) stepwise therapy from six hospitals in China. Patients were categorized into two groups based on whether they responded to anticoagulation therapy. The predictive performance of the DTSS system was evaluated through the efficacy of anticoagulation therapy, the area under the receiver operating characteristic curve (AUROC), calibration curve, decision curve analysis (DCA), and clinical impact curve (CIC) analysis. Results The response rates to anticoagulation therapy varied among patients with DTSS of different severity, being 94.12% for mild, 57.81% for moderate, and 13.33% for severe cases. The DTSS system demonstrated a robust predictive performance, with an AUROC of 0.864. The calibration curve indicated a close match between the predicted and observed effects of the DTSS system. Good calibration was confirmed by the Hosmer–Lemeshow test ( p = 0.704), and both the DCA and CIC analysis indicated high clinical utility of the DTSS system. Conclusion The DTSS system is a practical tool that uses easily accessible data to predict the initial response to anticoagulation therapy in PA‐HSOS patients, showing robust predictive performance and significant clinical benefit in guiding personalized management strategies.