Development and validation of an instrument to measure asthma symptom control in children

Few instruments exist to measure control of asthma symptoms in children. A brief instrument administered at healthcare visits could provide a more consistent approach to symptom recognition for patients and providers.

To develop a Pediatric Asthma Control Tool to measure asthma symptom control at pediatric healthcare visits and evaluate the instrument compared to expert assessment and an asthma-related quality-of-life (QOL) measure.

A preliminary 14-item instrument was generated through a process of literature review, meetings of institutional experts, and focus groups of parents and providers. The preliminary survey measured asthma control over the past 3 months in 2 domains: frequency of asthma flares and presence of symptoms when the child was at their best. Persistent symptoms were categorized according to published national asthma guidelines (NAEPP). The instrument and an asthma-related QOL measure were administered in the waiting room before a specialist visit for asthma. After the visit the specialist independently assessed asthma control in both domains on a 7-point Likert scale. Internal consistency and assessments of criterion and construct validity were calculated using standard statistics.

A total of 200 subjects ranging from 1 to 18 years of age and their caregivers were enrolled; 60% were male. During the prior 3 months, 19% had an emergency visit and 24% described persistent asthma symptoms. After item review the instrument was shortened to five items each for frequency of flares and symptoms at best. Internal consistency was high for each of these domains (Cronbach's alpha = 0.81/0.83, respectively). Correlation of each domain was good when compared to expert assessment (r = 0.54/0.59) and QOL (r = 0.61/0.77).

Responses to a 10-item instrument to measure control of asthma symptoms in children at a healthcare visit demonstrated internal consistency and criterion and construct validity.