Incidence and predisposing factors of infection in patients treated with hypomethylating agents.

Objective: Hypomethylating agents may have adverse effects such as cytopenias, cytopenia associated infections and fatality due to infections despite their favorable effects in the treatment of acute myeloid leukemia (AML), myelodysplastic syndromes (MDS) and chronic myelomonocytic leukemia (CMML). The infection prophylaxis approach is based on expert opinions and real-life experiences. Hence, we aimed to reveal the frequence of infections, predisposing factors of infection and to analyse infection attributable mortality in patients with high-risk MDS, CMML and AML who received hypomethylating agents in our center where routine infection prophylaxis is not applied.

Material-method: 43 adult patients with AML or high-risk MDS or CMML who received HMA ≥ 2 consecutive cycles from January 2014 to December 2020 were enrolled in the study.

Results: 43 patients and 173 treatment cycles were analyzed. The median age was 72 years and 61.3 % of patients were males. The distribution of the patients' diagnoses was; AML in 15 patients (34.9 %), high risk MDS in 20 patients (46.5 %), AML with myelodysplasia-related changes in 5 patients (11.6 %) and CMML in 3 patients (7 %). 38 infection events (21.9 %) occurred in 173 treatment cycles. 86.9 % (33 cycles) and 2.6 % (1 cycle) of infected cycles were bacterial and viral infections, respectively and 10.5 % (4 cycles) were bacterial and fungal concurrently. The most common origin of the infection was respiratory system. Hemoglobin count was lower and CRP level was higher at the beginning of the infected cycles significantly (p values were 0.002 and 0.012, respectively). Requirement of red blood cell and platelet transfusions were found to be significantly increased in the infected cycles (p values were 0.000 and 0.001, respectively). While > 4 cycles of treatment and increased platelet count were found to be protective against infection, > 6 points of Charlson Comorbidity Index (CCI) were found to increase the risk of infection. The median survival was 7.8 months in non-infected cycles while 6.83 months in infected cycles. This difference was not statistically significant (p value was 0.077).

Discussion: The prevention and management of infections and infection-related deaths in patients treated with HMAs is crucial. Therefore, patients with a lower platelet count or a CCI score of > 6 may be candidates for infection prophylaxis when exposed to HMAs.