Interstitial lung diseases specific measures in exercise interventions: A systematic review of measurement properties

BACKGROUND: Effects of exercise-based interventions (EBIs) on people with interstitial lung disease (ILD) are not yet fully understood. Reasons may include the limited use of ILD-specific measures and/or the lack of adequate information regarding their measurement properties. The purpose of this review was to summarize the ILD-specific outcome measures used in EBI studies and their measurement properties. METHODS: This was a two-phase systematic review: phase 1 identified ILD-specific measures used in EBI studies; phase 2 reviewed their measurement properties. PubMed, Web of Science, Scopus, EBSCO and EMBASE were searched up to March 2021. One reviewer extracted data, and 2 reviewers independently assessed studies risk of bias as well as the quality of measurement properties using the Consensus-Based Standards for the Selection of Health Status Measurement Instruments (COSMIN) recommendations. RESULTS: Phase 1 identified 18 records. The St George's Respiratory Questionnaire for Interstitial Pulmonary Fibrosis (SGRQ-IPF) was the only ILD-specific outcome measure used (n = 2 trials). Phase 2 resulted in 31 eligible records; measurement properties were reported for 12 measures. Measures presented sufficient content validity, internal consistency (Cronbach's alpha 0.61-0.96), test-retest reliability (intraclass correlation coefficient 0.39; 0.96), hypothesis testing and responsiveness but were insufficient for measurement error and indeterminate for cross-cultural and structural validity. The outcome measures King's Brief Interstitial Lung Disease and SGRQ-IPF had higher evidence of adequate measurement properties than other measures. Quality of the evidence was mostly very low to moderate. CONCLUSIONS: ILD-specific outcome measures are used infrequently in EBI trials, and there is scarce information regarding their measurement properties. DATABASE REGISTRATION: CRD42018112466.