Incidence and Predictors of Community-Acquired Pneumonia in Patients With Hematological Cancers Between 2016 and 2019

BACKGROUND: Patients with hematological cancers (HC) are at high risk of infections, in particular community-acquired pneumonia (CAP). Recent data on incidence and predictors of CAP among patients with HC are scarce. METHODS: We performed a cohort study (2016-2019) in 2 hospitals in the Netherlands among adults with HC to calculate incidence rates (IRs) of CAP. In addition, we performed a nested case-control study to identify predictors of CAP. RESULTS: We identified 275 CAP cases during 6264 patient-years of follow-up. The IR of CAP was 4390/100 000 patient-years of follow-up. Compared with the general population, IR ratios ranged from 5.4 to 55.3 for the different HCs. The case fatality and intensive care unit (ICU) admission rates were 5.5% and 9.8%, respectively. Predictors for CAP in patients with HC were male sex, anemia, lymphocytopenia, chronic kidney disease, cardiovascular disease, autologous and allogeneic stem cell transplantation, treatment with immunosuppressive medication for graft-vs-host disease, treatment with rituximab in the past year, and treatment with immunomodulators (lenalidomide, thalidomide, pomalidomide and/or methotrexate) in the past month. Independent predictors of a severe disease course (death or ICU admission) included neutropenia (odds ratio, 4.14 [95% confidence interval, 1.63-10.2]), pneumococcal pneumonia (10.24 [3.48-30.1]), chronic obstructive pulmonary disease (6.90 [2.07-23.0]), and the use of antibacterial prophylaxis (2.53 [1.05-6.08]). CONCLUSIONS: The burden of CAP in patients with HC is high, with significant morbidity and mortality rates. Therefore, vaccination against respiratory pathogens early in the disease course is recommended, in particular before starting certain immunosuppressive therapies.