Interpretation of treatment changes in 6-minute walk distance in patients with COPD
- 1 September 2008
- journal article
- research article
- Published by European Respiratory Society (ERS) in European Respiratory Journal
- Vol. 32 (3), 637-643
- https://doi.org/10.1183/09031936.00140507
Abstract
There is uncertainty about the interpretation of changes in the 6-min walk distance (6MWD) in chronic obstructive pulmonary disease (COPD) patients and whether the minimal important difference (MID) for this useful outcome measure exists. Data were used from nine trials enrolling a wide spectrum of COPD patients with 6MWD at baseline and follow-up and used to determine threshold values for important changes in 6MWD using three distribution-based methods. Anchor-based methods to determine a MID were also evaluated. Data were included of 460 COPD patients with a mean±sd forced expiratory volume in one second (FEV1) of 39.2±14.1% predicted and 6MWD of 361±112 m at baseline. Threshold values for important effects in 6MWD were between 29 and 42 m, respectively, using the empirical rule effect size and the standardised response mean. The threshold value was 35 m (95% confidence interval 30–42 m) based on the standard error of measurement. Correlations of 6MWD with patient-reported anchors were too low to provide meaningful MID estimates. 6-min walk distance should change by ∼35 m for patients with moderate to severe chronic obstructive pulmonary disease in order to represent an important effect. This corresponds to a 10% change of baseline 6-min walk distance. The low correlations of 6-min walk distance with patient-reported anchors question whether a minimal important difference exists for the 6-min walk distance.Keywords
This publication has 41 references indexed in Scilit:
- Managing Chronic Obstructive Pulmonary Disease in the CommunityJournal of Cardiopulmonary Rehabilitation, 2005
- How should COPD patients exercise during respiratory rehabilitation? Comparison of exercise modalities and intensities to treat skeletal muscle dysfunctionThorax, 2005
- Evaluation of the minimal important difference for the feeling thermometer and the St. George's Respiratory Questionnaire in patients with chronic airflow obstructionJournal of Clinical Epidemiology, 2003
- Methods to Explain the Clinical Significance of Health Status MeasuresMayo Clinic Proceedings, 2002
- LONG-TERM EFFECTS OF A PULMONARY REHABILITATION PROGRAMME IN OUTPATIENTS WITH CHRONIC OBSTRUCTIVE PULMONARY DISEASE: A RANDOMIZED CONTROLLED STUDYJournal of Rehabilitation Medicine, 1999
- The effects of a community-based pulmonary rehabilitation programme on exercise tolerance and quality of life: a randomized controlled trialEuropean Respiratory Journal, 1997
- Determining a minimal important change in a disease-specific quality of life questionnaireJournal of Clinical Epidemiology, 1994
- Randomised controlled trial of weightlifting exercise in patients with chronic airflow limitation.Thorax, 1992
- A measure of quality of life for clinical trials in chronic lung disease.Thorax, 1987
- Randomised controlled trial of rehabilitation in chronic respiratory disability.Thorax, 1981