Validity and reliability of outcome measures to assess dysfunctional breathing: a systematic review

Objective This study aimed to systematically review the psychometric properties of outcome measures that assess dysfunctional breathing (DB) in adults. Methods Studies on developing and evaluating measurement properties to assess DB were included. The study investigated the empirical research published between 1990 and February 2022, with an updated search in May 2023 in the Cochrane Library database of systematic reviews and the Cochrane Central Register of Controlled Trials, the Ovid Medline (full), the Ovid Excerta Medica Database, the Ovid allied and complementary medicines database, the Ebscohost Cumulative Index to Nursing and Allied Health Literature and the Physiotherapy Evidence Database. The included studies’ methodological quality was assessed using the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) risk of bias checklist. Data analysis and synthesis followed the COSMIN methodology for reviews of outcome measurement instruments. Results Sixteen studies met the inclusion criteria, and 10 outcome measures were identified. The psychometric properties of these outcome measures were evaluated using COSMIN. The Nijmegen Questionnaire (NQ) is the only outcome measure with ‘sufficient’ ratings for content validity, internal consistency, reliability and construct validity. All other outcome measures did not report characteristics of content validity in the patients’ group. Discussion The NQ showed high-quality evidence for validity and reliability in assessing DB. Our review suggests that using NQ to evaluate DB in people with bronchial asthma and hyperventilation syndrome is helpful. Further evaluation of the psychometric properties is needed for the remaining outcome measures before considering them for clinical use. PROSPERO registration number CRD42021274960. Data are available in a public, open access repository. All the relevant data were available at .