Epidemiology and Risk Factors for Infections in Myelodysplastic Syndromes

Background: Patients with MDS are at high risk of developing infections, which still represent the most frequent complications and the main cause of mortality and morbidity. We conducted a retrospective study with the aim of evaluating incidence, characteristics and outcome of infectious events in patients with myelodysplastic syndromes (MDS) and the risk factors associated with them.

Patients and methods: 200 patients with MDS or LMMC followed by the Ancona Hematology Clinic in the last 15 years were included. In this group, we evaluated severe infectious episodes and associated risk factors, relating to patient, disease and therapy.

Results: In a cohort of 200 patients, we detected 65 cases of infections of higher than third grade according to WHO. Pneumonia is the most frequent infection, especially on a bacterial basis. Risk factors that have shown significant association with infections ≥ G3 are: comorbidity (p = 0.0086), hemoglobin level (P = 0.0111), neutropenia (P = 0.0152), transfusion dependence during the course of disease (P <0.0001) and hypomethylating therapy (P = 0.0014). A subanalysis confirmed comorbidities as risk factors for the development of pneumonia (P = 0.0322) and azacitidine therapy as a risk factor for sepsis (P = 0.0038). The overall survival of the cohort is approximately 7.5 months and the predictive factors of survival are patient age (P = 0.0005), WHO disease class (P = 0.001), R-IPSS (P <0.0001) and transfusion-dependence during the course of the disease (P <0.0001). Multivariate analysis confirmed age (P = 0.0002), R-IPSS (P = 0.0043) and transfusion-dependence (P = 0.0006) as predictors of survival. Infections above grade 3 do not impact survival. Otherwise, there was a trend of reduced survival in patients who had pneumonia (P = 0.0612) or sepsis (P = 0.0927).

Conclusion: Patients with MDS have a high probability of encountering an infectious problem in the course of the natural history of the disease. In one out of five cases, there are more than one infectious event. Particularly at risk of infection are patients with comorbidities, neutropenia (PMN <800 / mm³), significant transfusion needs and on therapy with hypomethylating agents. These patients should be carefully monitored for infectious complications.