Validation of test performance characteristics and minimal clinically important difference of the 6-minute walk test in patients with idiopathic pulmonary fibrosis. Issue 7 (July 2015)

• Record Type: Journal Article
• Authors: Nathan, Steven D.; du Bois, Roland M.; Albera, Carlo; Bradford, Williamson Z.; Costabel, Ulrich; Kartashov, Alex; Noble, Paul W.; Sahn, Steven A.; Valeyre, Dominique; Weycker, Derek; King, Talmadge E.
• Is Part Of: Respiratory medicine. Volume 109:Issue 7(2015)
• Page Start: 914
• Page End: 922
• Publication Date: 2015-07
• Subjects: Chest -- Diseases -- Periodicals; Chest -- Diseases -- Great Britain -- Periodicals; Respiratory organs -- Diseases -- Periodicals; Respiratory Tract Diseases -- Periodicals; Appareil respiratoire -- Maladies -- Périodiques; Thorax -- Maladies -- Périodiques; Appareil respiratoire -- Maladies -- Traitement -- Périodiques; Electronic journals; 616.2
• DOI: 10.1016/j.rmed.2015.04.008
• Languages: English
• ISSNs: 0954-6111

Abstract

<abstract xml:lang="en" abstract-type="author" id="abs0010"> <title id="sectitle0010">Summary</title> <sec> <title id="sectitle0015">Background</title> <p id="abspara0010">The 6-minute walk test distance (6MWD) has been shown to be a valid and responsive outcome measure in patients with idiopathic pulmonary fibrosis (IPF). The analyses were based, however, on a single phase 3 trial and require validation in an independent cohort.</p> </sec> <sec> <title id="sectitle0020">Objective</title> <p id="abspara0015">To confirm the performance characteristics and estimates of minimal clinically important difference (MCID) of 6MWD in an independent cohort of patients with IPF.</p> </sec> <sec> <title id="sectitle0025">Methods</title> <p id="abspara0020">Patients randomized to placebo in the phase 3 CAPACITY trials who had a baseline 6MWD measurement were included in these analyses. The 6MWD and other functional parameters (lung function, dyspnea, and health-related quality of life) were measured at baseline and 24-week intervals. Validity and responsiveness were examined using Spearman correlation coefficients. The MCID was estimated using distribution- and anchor-based methods.</p> </sec> <sec> <title id="sectitle0030">Results</title> <p id="abspara0025">The analysis comprised 338 patients. Baseline 6MWD was significantly correlated with lung function measures, patient-reported outcomes, and quality-of-life measures (validity). Compared with baseline 6MWD, change in 6MWD (responsiveness) showed stronger correlations with change in lung function parameters and quality-of-life measures. Dyspnea measured by the University of California San Diego Shortness of Breath Questionnaire showed the strongest correlations with 6MWD (baseline: coefficient −0.35; 48-week change: coefficient −0.37; both p < 0.001). The distribution-based analyses of MCID using standard error of measurement yielded an MCID of 37 m, and distribution-based analyses by effect size resulted in 29.2 m. The MCID by anchor-based analysis using criterion referencing (health events of hospitalization or death) was 21.7 m.</p> </sec> <sec> <title id="sectitle0035">Conclusions</title> <p id="abspara0030">The 6MWD is a valid and responsive clinical endpoint, which provides objective and clinically meaningful information regarding functional status and near-term prognosis. These results confirm previous findings in an independent cohort of patients with IPF.</p> </sec> </abstract>