Development and validation of a questionnaire to assess asthma control in pediatrics

Objective: To develop and validate a questionnaire to assess asthma control in children (CAN).

Design: Two versions of the CAN (for carers and children) were developed. Both versions were validated in an observational, prospective, multicenter study performed in 38 hospital outpatient clinics throughout Spain. Four hundred fifteen patients and their carers agreed to participate. Of these, 414 patients under 14 years old with frequent episodic or persistent (moderate to severe) asthma completed the questionnaire on 3 occasions (baseline, week 2, and week 12). For patients aged 2-8 the questionnaire was only completed by the carers, but for patients aged 9-14 the questionnaire was completed by the carers and the children. Clinician ratings of asthma control were used as a gold standard to assess the sensitivity, specificity, PPV and NPV of the new measure.

Results: Evaluable responses were obtained from 215 carers for children aged 2-8 years and 199 children aged 9-14 years, and their parents. Using a questionnaire total score cut-off of 8 the patient version had a sensitivity of 76.3% and a specificity of 62.9%. For carer version these values were 73% and 69.7%, respectively. A cut point of 8 was selected to maximize the screening accuracy of the CAN questionnaire. Effect sizes in patients with clinician-rated improvements in asthma control were 0.33 and 0.57 for the carer and child versions, respectively.

Conclusions: The screening accuracy and validity of the CAN questionnaire make it suitable for use in research and clinical practice. The sensitivity and specificity were close to 70%, which is acceptable for the study objective: obtain a tool to measure the level of asthma control.