Infections in patients with aplastic Anemia in Chiang Mai University.

Background: Infection is a major complication in aplastic anemia (AA) patients. Primary objectives of this study were to determine the prevalence of infections and to determine types of pathogens associated with infections in patients with AA. Secondary objectives were to evaluate overall survival after infections as well as risk factors of infections in patients with AA.

Methods: The authors retrospectively evaluated the infectious episodes (IEs), type of infections, associated pathogens, and outcomes of infections in patients with AA who were diagnosed and treated at Chiang Mai University between January 2010 and December 2015.

Results: Sixty-seven patients with a median age of 51 years (range, 15-87 years) were enrolled. Forty two patients (62.6%) were severe AA. Median absolute neutrophil count (ANC) was 984 /mm³ (range, 120-5500/mm³). Twenty five patients (37.3%) received antithymocyte globulin plus cyclosporine A, 41 patients (61.1%) received anabolic hormone, and 2 patients (2.9%) underwent allogeneic hematopoietic stem cell transplantation. Overall, 31 IEs were documented in 22 patients (32.8%). The most common microbiologically documented site of infection was bloodstream infection (23.4%) followed by pulmonary infection (14.9%). Culture-negative febrile neutropenia occurred in 12.7%. Common pathogens identified were bacteria (73.9%), mainly gram-negative (52.9%) including Acinetobacter baumannii (23.5%) and Pseudomonas aeruginosa (17.6%). Fungal infections were diagnosed in 21.7% and all were Aspergillus spp. Six patients (9%) died during the study period. All of them died from infection which gram-negative bacteria were most common pathogens (66.7%). Patients with infections had 5-year overall survival of 72% that is significantly less than patients without infection (100%) (p = 0.0002). Only risk factor that correlates with high probability of infection was ANC < 500/mm³. (HR 2.29, 95%CI 1.03-7.72, p = 0.043).

Conclusions: Prevalence of infections in AA patients in Chiang Mai University was 32.8% Bacterial infections especially gram-negative bacteria were the major pathogens. Patients with ANC < 500/mm³ had higher risk of infections. Infection was the most important cause of death in AA.