A Prognostic Model for Predicting the Impact of Comorbidities on Survival of Patients with Myelodysplastic Syndromes.
Authors: Porta Matteo G. Della , Malcovati Luca , Travaglino Erica , Pascutto Cristiana , Maffioli Margherita , Invernizzi Rosangela , Cazzola Mario 
Published: April 2020

Abstract
Myelodysplastic syndromes (MDS) occur mainly in older persons, and these patients are likely to have comorbidities. We studied the impact of comorbidities on non-leukemic death (NLD) and overall survival (OS) in MDS patients with the aim of developing a specific prognostic index. Eight hundred forty consecutive patients receiving a diagnosis of MDS at Policlinico San Matteo, Pavia, Italy, between 1992 and 2006 were retrospectively evaluated. One or more comorbidities were present in 455/840 (54%) patients: the older the age, the higher their prevalence (P&lt;0.001). Cardiac disease was observed in 25% of patients, liver disease in 16%, diabetes in 11%, prior solid tumor in 10%, nephropathy and pulmonary disease in 4%. Non-leukemic causes of death included cardiac failure (63%), infection (24%) and hemorrhage (7%). In a Cox analysis with age, sex, WHO category, cytogenetics and transfusion-dependency as time-dependent covariates, the presence of one or more comorbidities significantly affected both the risk of NLD (HR=1.91, P=0.001) and OS (HR=1.51, P=0.01), while it did not influence the risk of leukemic progression. The negative effect of comorbidities on OS was more evident in patients without excess of blasts (HR=1.8 P=0.007), while it retained a borderline significance in patients with more advanced disease (P=0.05). By including comorbidities as distinct entities in multivariable analysis, cardiac failure, liver or pulmonary disease, and solid tumors were found to independently affect the risk of NLD (HR=3.7, HR=2.08, HR=2.07 HR=2.23, respectively; P values from &lt;0.001 to 0.033). Based on results of uni- and multivariable analysis, we developed a prognostic model for predicting the effect of comorbidities on NLD and OS. For each comorbidity, risk scores were estimated from the coefficients of the Cox regression. This MDS-specific comorbidity index (MDS-CI) allowed us to identify 3 groups of patients with different probability of NLD and OS (HR 2.78, P&lt;0.001; HR 1.67 P=0.001), and provided a better stratification than the available non MDS-specific indices. Focusing on WPSS categories [J Clin Oncol2007; 25:3503–10], MDS-CI significantly stratified survival of patients with very-low, low and intermediate risk groups (P&lt;0.001), while it had no effect in high and very-high risk groups. We then investigated the relationship between transfusion-dependency, secondary iron overload and comorbidities. Heart failure (28% vs. 18% P=0.001) and cardiac death (69% vs 55% P=0.03) were significantly more frequent in transfusion-dependent patients. In a Cox analysis with time-dependent covariates, transfusion-dependent patients showed an increased risk of NLD (HR=2.12 P=&lt;0.001), heart failure (HR 1.34 P=0.03), and cardiac death (HR 2.99 P=0.01). The development of secondary iron overload significantly affected the risk of NLD and OS (HR=1.25 and 1.16 respectively, P&lt;0.001), and this effect was maintained after adjusting for transfusion burden. Iron overload specifically increased the risk of developing heart failure (HR=1.17, P&lt;0.001). In summary, the presence of non-hematological comorbidities significantly worsens the survival of MDS patients. Transfusion-dependency and secondary iron overload are associated with an increased risk of cardiac complications and cardiac death. The MDS-CI might be a useful tool for clinical decision making in patients with myelodysplastic syndromes.