PT  - JOURNAL ARTICLE
AU  - Amy Po Yu Tsai
AU  - Seo Am Hur
AU  - Alyson Wong
AU  - Mohsen Safavi
AU  - Deborah Assayag
AU  - Kerri A Johannson
AU  - Julie Morisset
AU  - Charlene Fell
AU  - Jolene H Fisher
AU  - Hélène Manganas
AU  - Shane Shapera
AU  - Gerard Cox
AU  - Andrea S Gershon
AU  - Nathan Hambly
AU  - Nasreen Khalil
AU  - Teresa To
AU  - Pearce George Wilcox
AU  - Andrew Halayko
AU  - Martin RJ Kolb
AU  - Christopher J Ryerson
TI  - Minimum important difference of the EQ-5D-5L and EQ-VAS in fibrotic interstitial lung disease
AID  - 10.1136/thoraxjnl-2020-214944
DP  - 2020 Oct 06
TA  - Thorax
PG  - thoraxjnl-2020-214944
4099  - http://thorax.bmj.com/content/early/2020/10/06/thoraxjnl-2020-214944.short
4100  - http://thorax.bmj.com/content/early/2020/10/06/thoraxjnl-2020-214944.full
AB  - Rationale The European Quality of Life 5-Dimensions 5-Levels questionnaire (EQ-5D-5L) is a multidimensional patient-reported questionnaire that supports calculation of quality-adjusted life-years. Our objectives were to demonstrate feasibility of use and to calculate the minimum important difference (MID) of the EQ-5D-5L and its associated visual analogue scale (EQ-VAS) in patients with fibrotic interstitial lung disease (ILD).Methods Patients who completed the EQ-5D-5L were identified from the prospective multicentre CAnadian REgistry for Pulmonary Fibrosis. Validity, internal consistency and responsiveness of the EQ-5D-5L were assessed, followed by calculation of the MID for the EQ-5D-5L and EQ-VAS. Anchor-based methods used an unadjusted linear regression against pulmonary function tests (PFTs) and dyspnoea and other quality of life questionnaires. Distribution-based method used one-half SD and SE measurement (SEM) calculations.Results 1816 patients were analysed, including 472 (26%) with idiopathic pulmonary fibrosis. EQ-5D-5L scores were strongly correlated with the dyspnoea and other quality of life questionnaires and weakly associated with PFTs. The estimated MID for EQ-5D-5L ranged from 0.0050 to 0.054 and from 0.078 to 0.095 for the anchor-based and distribution-based methods, respectively. The MID for EQ-VAS ranged from 0.5 to 5.0 and from 8.0 to 9.7 for the anchor-based and distribution-based methods. Findings were similar across ILD subtypes, sex and age.Conclusion We used a large and diverse cohort of patients with a variety of fibrotic ILD subtypes to suggest validity and MID of both the EQ-5D-5L and EQ-VAS. These findings will assist in designing future clinical trials and supporting cost-effectiveness analyses of potential treatments for patients with fibrotic ILD.