Predictive Value of the Hematopoietic Stem Cell Transplantation - Comorbidity Index for Overall Survival in Patients with Multiple Myeloma

Aim: The scoring system of the hematopoietic cell transplantation comorbidity index (HCT-CI) was used in patients with multiple myeloma (MM) undergoing autologous stem cell transplantation (ASCT), and it could predict progress-free survival and overall survival. Our study aims to determine the ideal cut-off value for the HCT-CI score, which can be effective in showing overall survival in patients with MM undergoing ASCT. Methods: The files of all MM patients with ASCT between January 2015 and December 2020 were retrospectively scanned. The X-tile model was used to determine the cut-off values of the HCT-CI score. Survival probabilities were calculated using the Kaplan-Meier estimator. The Cox proportional hazard regression model was used for univariate and multivariate analyses. Results: Patients were divided into two categories according to HCT-CI. Score <= 6 was defined as low-risk (n=93, 81.6%), and score >6 was defined as high-risk (n=21, 18.4%). The low-risk group had one-year and two-year OS rates of 96.7% and 86.9%, respectively, while the high-risk group had rates of 69.9% and 40.3% (p<0.001). In multivariate regression analysis, only being older than 70 years and having a HCT-CI >6 were found to be significant, with an HR of 3,718 and 5,543, respectively. Conclusion: Hematopoietic stem cell transplantation - comorbidity index score >6 can aid physicians in deciding whether to perform ASCT in MM patients and predict the overall survival of those patients.