Patient Related Outcome Measures (Feb 2021)
Psychometric Validation of the EQ-5D-3L in Patients with Nontuberculous Mycobacterial (NTM) Lung Disease Caused by Mycobacterium avium Complex (MAC)
Abstract
Anuj Shah,1 Xinyi Ng,1 Ruchit Shah,1 Caitlyn Solem,1 Ping Wang,2 Marko Obradovic3 1Patient Centered Outcomes, Pharmerit – An OPEN Health Company, Bethesda, MD, USA; 2Health Economics and Outcomes Research, Insmed Incorporated, Bridgewater Township, NJ, USA; 3Health Economics and Outcomes Research, Insmed Germany GmbH, Frankfurt am Main, GermanyCorrespondence: Marko ObradovicSenior Director, HEOR Europe, Insmed Germany GmbH, The Square 12, am Flughafen, Frankfurt (Frankfurt am Main), 60549, GermanyEmail [email protected]: This analysis evaluated the psychometric properties of the EQ-5D-3L among patients with Mycobacterium avium complex lung disease (MAC-LD).Methods: Data from the Phase III CONVERT trial were analyzed. Study measures including the EQ-5D-3L, St. George’s Respiratory Questionnaire (SGRQ), the 6-minute walk test (6MWT), and percent predicted forced expiratory volume in 1 second (ppFEV1) were collected at baseline, month 3 (M3), month 4 (M4; only 6MWT), and month 6 (M6). Item characteristics and validity were evaluated at baseline. Test–retest reliability was assessed using intraclass correlation coefficients (ICC) and a weighted kappa statistic among a subgroup of stable patients. Validity was tested by evaluating correlations of the EQ-5D-3L index/visual analogue scale (VAS) scores with SGRQ and 6MWT and comparing mean index/VAS scores across known groups defined using 6MWT and ppFEV1. Responsiveness of the EQ-5D-3L was assessed using 6MWT, SGRQ, ppFEV1, and culture conversion as anchors.Results: The index score was subject to ceiling effects, with 32.6% of patients reporting perfect health at baseline. ICCs for the index (0.80) and VAS (0.85) scores and weighted kappas for the domains (0.5– 0.72) indicated adequate test–retest reliability. Correlations between the index/VAS scores and related domains of the SGRQ and 6MWT were as hypothesized (0.31– 0.62), and the mean index/VAS scores were significantly different between the 6MWT and ppFEV1 known groups (p< 0.05), supporting the validity of the EQ-5D-3L. No evidence was found supporting the responsiveness of the EQ-5D-3L to changes in any of the anchors.Conclusion: EQ-5D-3L exhibited evidence of validity and reliability but poor responsiveness to clinically meaningful changes in patients with MAC-LD.Keywords: psychometric validation, NTM lung disease, EQ-5D, reliability, validity, responsiveness
