Asthma Is Associated with Acute Chest Syndrome, but Not an Increase Rate of Hospitalization for Pain among Children with Sickle Cell Anemia: A Retrospective Cohort Study.

Introduction In this study, we sought to validate the previous findings that asthma increases the incidence of acute chest syndrome (ACS) and pain in children with sickle cell anemia (SCA).

Methods A retrospective cohort was comprised of children with SCA evaluated for at least six months from a single medical center. Asthma was defined as being present when the first wheezing episode was heard by a physician after the age of 2 years or after 3 episodes of bronchiolitis before the age of 2 years. ACS was defined as a recent abnormal X-ray of the lungs associated with fever, respiratory signs or thoracic pain. A painful episode was defined as pain that resulted in hospitalization. Therapeutic intervention (hydroxyurea, blood transfusion therapy or transplant) was uniformly applied to all children with three or more episodes of pain that required hospitalization within a 12 month period. Patient years were accumulated from birth until death, lost to follow up, last visit to the center or a therapeutic intervention, whichever came first.

Results A total of 297 children with SCA were evaluable for a doctor diagnosis of asthma for a total of 1,805 patient-years. The mean length of follow-up was 6.1 patient-years. A doctor diagnosis of asthma was present in 8.4% (25 of 297). Among the children with asthma 75% (19 of 25) were consistently prescribed a beta 2 agonist or inhaled corticosteroids. After adjustment for the effect of age, asthma was significantly associated with ACS event (p = 0.03) but pain was not (>0.05).

Conclusion Among children with SCA, asthma is associated with an increased incidence of ACS, but not pain that required hositalization. The absence of an association between asthma and pain may be related to uniform therapeutic intervention for children with repetitive painful episodes that require hospitalizations coupled with active treatment for asthma in most of the children.