TY - JOUR T1 - Short- and Long-Term Reliability of the 6-Minute Walk Test in People With Idiopathic Pulmonary Fibrosis JF - Respiratory Care SP - 994 LP - 1001 DO - 10.4187/respcare.05875 VL - 63 IS - 8 AU - Anne E Holland AU - Catherine J Hill AU - Leona Dowman AU - Ian Glaspole AU - Nicole Goh AU - Annemarie L Lee AU - Christine F McDonald Y1 - 2018/08/01 UR - http://rc.rcjournal.com/content/63/8/994.abstract N2 - BACKGROUND: The aim of this work was to investigate the short- and long-term test-retest reliability of the 6-min walk distance (6MWD), peak heart rate, and nadir oxygen desaturation in idiopathic pulmonary fibrosis (IPF).METHODS: A reliability study of 70 adults with IPF was undertaken within out-patient pulmonary rehabilitation programs at 2 tertiary hospitals. Participants completed 2 baseline 6-min walk tests using a standard protocol, with continuous measures of percutaneous SpO2 and heart rate via pulse oximetry. The 6-min walk test was completed immediately following an intervention period and 6 months after. Reproducibility was assessed by intraclass correlation coefficient and Bland-Altman analysis.RESULTS: Participants with a mean ± SD diffusing capacity of the lung for carbon monoxide of 48 ± 14% were included. The reliability of the 6MWD was high (intraclass correlation coefficient = 0.96) with a mean learning effect of 21 m (95% CI 12–30 m). The learning effect persisted at 8 weeks (mean 14 m, 95% CI 5–23 m) but not 6 months (mean 15 m, 95% CI −1 to 30 m). Using the best (greatest) 6MWD significantly reduced the proportion of participants who were classified as having a clinically important response to rehabilitation compared with using the first 6MWD (40% vs 54%, P = .002). Nadir SpO2 was reproducible, with a mean difference of 0.7 ± 2.2%, and limits of agreement of −4 to 5%. Peak heart rate was more variable, with mean difference 5 ± 9 beats/min and limits of agreement of −12 to 20 beats/min.CONCLUSIONS: The 6MWD is a reproducible measure of exercise capacity in people with IPF. Whereas the nadir SpO2 may be accurately determined from one test, evaluating change in 6MWD with interventions may require 2 tests on each occasion. (ClinicalTrials.gov registration NCT0016828.) ER -