Painful Episodes in Children with Sickle Cell Disease and Asthma Are Temporally Associated with Respiratory Symptoms.

Background: Previously our research group demonstrated that a diagnosis of asthma is associated with an increased rate of painful episodes in children with sickle cell disease (SCD); however, little is known about the temporal relationship between an asthma exacerbation and a painful episode in a child with SCD. We tested the hypothesis that respiratory symptoms either precede or occur concomitantly with painful episodes more frequently in children with SCD and asthma when compared to children without asthma.

Methods: As part of standard care, a cohort study was conducted. The primary hematologist referred all children with SCD for evaluation by a pulmonologist. The definition of asthma was based on the National Heart Lung and Blood Institute’s guidelines. The primary outcome recorded was respiratory symptoms occurring up to 96 hours prior to a painful episode. Respiratory symptoms were defined as any of the following:

1. cough

2. wheeze

3. tachypnea

4. retractions, or

5. grunting.

Pain was defined as the complaint of body pain (excluding the head) requiring the administration of opioids in the hospital, clinic, or emergency department.. Cases and controls were children with and without asthma, respectively. Medical records from all hematology clinic, emergency department, and inpatient visits over a 25-month period were reviewed for painful episodes and the presence of respiratory symptoms.

Results: A total of 74 children were evaluated by a hematologist and referred to pulmonologist for an asthma between 6/15/2004 and 1/31/2005. Of the eligible patients, 36 were diagnosed with asthma (mean age 9.8 years; median 9.6 years; range 2.4–19.4) and 38 were determined not to have asthma (mean age, 9.8 years; median 9.7 years; range 2.4–19.5). For children with asthma versus those without asthma, the odds ratio of having a pain episode associated with antecedent or concurrent respiratory symptoms was 4.9 (95% confidence intervals, 2.2–10.7).

Conclusions: In children with both SCD and asthma, respiratory symptoms are a risk factor for subsequent painful episodes.