Asthma Screening in Pediatric Sickle Cell Disease: A Clinic-Based Program Using Questionnaires and Spirometry

A clinician diagnosis of asthma is associated with increased morbidity and mortality in people with sickle cell disease (SCD). We hypothesized that a screening program would help identify children with asthma needing referral to pulmonary clinic. We conducted a single-center project to screen patients with SCD for asthma using a previously validated questionnaire (Breathmobile) and for pulmonary function abnormalities with portable spirometry. Participants with a positive questionnaire and/or abnormal spirometry were referred to pediatric pulmonary clinic. We evaluated clinical associations with abnormal spirometry and questionnaire responses. Of the 157 participants, 58 (37%) had a positive asthma screening questionnaire. Interpretable spirometry was available for 105 (83% of those eligible) and of these, 35 (34%) had abnormal results. The asthma questionnaire was 87.5% sensitive [95% confidence interval (CI) 74.8-95.3] and 85.3% specific (95% CI 77.3-91.4) to detect a clinician diagnosis of asthma. Participants with positive questionnaires were older (mean age 12.2 vs. 9.9 years, P = 0.012). Spirometry identified 16 additional participants who had normal asthma questionnaires. Seventy-four participants (47%) were referred to pediatric pulmonary clinic and 25 (34%) of these participants scheduled clinic appointments; however, only 13 (52%) were evaluated in pulmonary clinic. Clinic-based asthma screening and spirometry frequently identified individuals with asthma and pulmonary function abnormalities. Only 22% of those referred were eventually seen in pulmonary clinic. The impact of improved screening and treatment on the pulmonary morbidity in SCD needs to be defined and is an area for future investigation. In addition, case management or multidisciplinary clinics may enhance future screening programs.