Development of a Thalassemia International Prognostic Scoring System (TIPSS)

Abstract

A prognostic scoring system that can differentiate beta-thalassemia patients based on mortality risk is lacking. We analysed data from 3145 beta-thalassemia patients followed through a retrospective cohort design for the outcome of death. An a priori list of prognostic variables was collected. beta Coefficients from a multivariate cox regression model were used from a development dataset (n = 2516) to construct a formula for a Thalassemia International Prognostic Scoring System (TIPSS) which was subsequently applied to a validation dataset (n = 629). The median duration of observation was 10.0 years. The TIPSS score formula was constructed as exp (1.4 x heart disease + 0.9 x liver disease + 0.9 x diabetes + 0.9 x sepsis + 0.6 x alanine aminotransferase >= 42 IU/L + 0.6 x he-moglobin <= 9 g/dL + 0.4 x serum ferritin >= 1850 ng/mL). TIPSS score thresholds of greatest differentiation were assigned as <2.0 (low-risk), 2.0 to <5.0 (intermediate-risk), and >= 5.0 (high-risk). The TIPSS score was a good predictor for the outcome of death in the validation dataset (AUC: 0.722, 95%CI: 0.641-0.804) and survival was significantly different between patients in the three risk categories (P < 0.001). Compared to low-risk patients, the hazard ratio for death was 2.778 (95%CI: 1.335-5.780) in patients with intermediate-risk and 6.431 (95%CI: 3.151-13.128) in patients with high-risk. This study provides a novel tool to support mortality risk categorization for patients with beta-thalassemia that could help management and research decisions.