The revised myeloma comorbidity index (R-mci) in multiple myeloma patients undergoing autologous hematopoietic stem cell transplantation: a retrospective analysis

Newly diagnosed multiple myeloma (MM) cases are mostly an elderly and heterogeneous patient group, and these cases are accompanied by disease-related or unrelated comorbidities. With the introduction of new agents in both transplant-eligible and non-eligible patients over the past ten years that increase median survival by up to 8–10 years, significant progress has been achieved in the treatment of MM. Myeloma Comorbidity Index (MCI) is a simple and valid comorbidity index including the risk factors of renal impairment, moderate to severe lung disease, and performance status in MM patients in order to prevent treatment-related drug toxicity, predicts overall and disease-free survival, and better determine the patient group that will benefit from treatment. Recently, the score was revised (R-MCI) by adding the factors of age, frailty, and cytogenetic aberrations. The R-MCI allows the definition of fit (R-MCI score ≤ 3), intermediate-fit (R-MCI scores 4–6), and frail (R-MCI score > 6) patients showing strong clinical relevance for OS and PFS. R-MKI also stands out as an easily applicable and accurate scoring system. In previous studies, R-MCI was mostly evaluated in the elderly population, and in this study, we aimed to investigate the success of R-MCI in predicting prognosis in relatively young patients with autologous hematopoietic stem cell transplantation.Our study included 95 patients older than 18 years of age who undewent autologous hematopoietic stem cell transplantation (ASCT) due to MM, followed in Bursa Uludag University Faculty of Medicine Hospital Hematology Department between January 2010 and December 2021, and patients data were analyzed retrospectively. Patients were split into two groups as fit and intermediate-fit, according to R-MCI scoring, and the accuracy of R-MCI in predicting overall and disease-free survival was examined. While the mean overall survival time of patients classified as fit was 109.73 months, it was found to be 75.31 months in patients in the intermediate-fit group. In terms of disease-free survival, no significant difference was observed in either group. Our study showed that R-MCI could predict disease-free survival even in the patient population with relatively less frail patients undergoing ASCT. The lack of frail patients in our study is one of the limitations. There are few studies reporting that R-MCI predicts prognosis in MM, our study contributes to the literature in this respect, and larger-scale prospective studies are needed.