The Composite Health Risk Assessment Model (CHARM) Predicts Overall Mortality and Relapse, But Not Non-Relapse Mortality, in Adults Following Unrelated Single-Unit Cord Blood Transplantation

Objective: Concerns about excessive non-relapse mortality (NRM) are a major issue following allogeneic hematopoietic cell transplantation (HCT). Although the HCT-Specific Comorbidity Index (HCT-CI) was established as a stratification model for NRM following allogeneic HCT, the Composite Health Risk Assessment Model (CHARM) score was also developed to predict the risk of NRM and overall mortality following allogeneic HCT from adult donors, particularly in older patients. The CHARM score has been shown to predict these outcomes better than the HCT-CI alone. However, the prognostic value of the CHARM score has not been validated in adult patients undergoing unrelated single-unit cord blood transplantation (CBT). This study aimed to address that gap in the research. Materials and Methods: We retrospectively validated the impact of the CHARM score on transplant outcomes in 321 adults who underwent unrelated single-unit CBT at our institution. Results: In univariate analysis, a higher CHARM score was significantly associated with worse overall mortality (p<0.001), higher relapse (p=0.007), and NRM (p=0.048). In multivariate analysis, the rates of overall mortality (hazard ratio [HR]: 1.56, 95% confidence interval [CI]: 1.06-2.29, p=0.022) and relapse (HR: 1.71, 95% CI: 1.09-2.69, p=0.020) were significantly higher in patients with higher CHARM scores, but NRM was not (HR: 1.17, 95% CI: 0.68-1.99, p=0.560). The detrimental effects of higher CHARM scores on overall mortality and relapse compared to lower CHARM scores were observed in subgroups of patients with high and very high risk, as defined by the refined Disease Risk Index. Conclusion: In contrast to previous research, this study revealed that the CHARM score was able to predict overall mortality and relapse, but not NRM, in adults undergoing single-unit CBT.