Epidemiology of infections in children with acquired aplastic anaemia: a retrospective multicenter study in Italy

Infection is a significant cause of death in patients with aplastic anaemia (AA). However, few studies have examined the characteristics of infections in patients with AA, especially in children. The aim of this retrospective study was to evaluate the incidence and types of infections in a large cohort of paediatric patients with AA referred to eight AIEOP (Italian Association of Paediatric Oncology and Haematology) centres in Italy. The study included 78 patients, 45 boys and 33 girls, median age 9.29 yrs (1st-3rd quartile 3.59-13.09) diagnosed with AA. During the study period, 111 infectious episodes were observed in 42 (54%) patients. Fifty-one (46%) episodes were fever of unknown origin and 60 (54%) were documented infections (DI). In this group, microbiologically documented infection (MDI) with bacteremia accounted for 23 (38%) episodes, MDI without bacteremia for 7 (12%), clinically documented infection for 25 (42%) and invasive fungal diseases for 5 (8%). The rate (episodes/1000 d at risk) was similar in severe aplastic anemia and very severe aplastic anemia both before and after day 120. During the first 120 d from diagnosis, the cumulative risk of a DI was 21% (95% CI 12-29) with the last episode at day 117, but the 50% of episodes were observed in the first 24 d. After day 120, the cumulative risk of DI was again 21% (95% CI 12-29), with the last episode at day 445 of follow-up, with 50% of episodes observed in the first 120 d of observation (240 d from the diagnosis of AA). We found a statistically significant association between the grade of aplasia at diagnosis and the incidence of IEs (P = 0.0002). No association was found between gender, age at diagnosis, response at day +120 and at day +180, use of G-CSF and occurrence of IEs. The actuarial overall survival at 5 yrs was 90% ± 3.6. The mortality rate attributable to infection complication was 9%. This is a large paediatric cohort study reporting the epidemiology of infectious complications in children with AA and that allow us to compare the epidemiological data in this diseases with that of the most recent studies in neutropenic children with cancer. Our findings confirm that infections represent the main cause of death in patients with AA and they are important for the design of management strategies of febrile neutropenia in these patients.