Validation of a Questionnaire for Assessing Adherence to Metered-Dose Inhaler Use in Asthmatic Children

Abstract

Maintenance therapies for asthma are vulnerable to low adherence. Clinicians would benefit from having a validated questionnaire to assess adherence to metered-dose inhaler use in children with asthma. The objective of this study was to design and validate a questionnaire assessing adherence to metered-dose inhaler use, to be filled out by the parents and/or caregivers of children with asthma. The six questions on the Pediatric Inhaler Adherence Questionnaire were obtained from reviewing the literature, from carrying out focus group discussions, and from the researchers' professional experience. We assessed concurrent criterion validity using canister weight change as the gold standard and also assessed test–retest reliability. The questionnaire was administered to the parents/caregivers of 64 children aged 3.6 ± 2.2 years. Questionnaire scores correlated positively with the absolute value of the difference between 100 and percent taken of prescribed (Spearman correlation coefficient rho = 0.42, p = 0.001). The sensitivity of the questionnaire in detecting nonadherent patients ranged from 50% to 75%; positive predictive value ranged from 23.1% to 66.7%; and likelihood ratio ranged from 1.5 to 5.5 for the detection of nonadherent patients. The Pediatric Inhaler Adherence Questionnaire is a valid, reliable, quick, inexpensive, and easy-to-use instrument that allows quantitative assessment of metered-dose inhaler adherence in children with asthma, and may be useful across a range of clinical and research settings.