PT  - JOURNAL ARTICLE
AU  - Michael Polkey
AU  - Martijn Spruit
AU  - Lisa Edwards
AU  - Michael Watkins
AU  - Vincent Pinto-Plata
AU  - Jørgen Vestbo
AU  - Peter Calverley
AU  - Ruth Tal-Singer
AU  - Alvar Agusti
AU  - Per Bakke
AU  - Harvey Coxson
AU  - David Lomas
AU  - William MacNee
AU  - Stephen Rennard
AU  - Edwin Silverman
AU  - Bruce Miller
AU  - Courtney Crim
AU  - Julie Yates
AU  - Emiel Wouters
AU  - Bartholeme Celli
TI  - The minimal clinically important difference (MCID) for the six minute walk (6MW) test in COPD in relation to death
DP  - 2012 Sep 01
TA  - European Respiratory Journal
PG  - P601
VI  - 40
IP  - Suppl 56
4099  - http://erj.ersjournals.com/content/40/Suppl_56/P601.short
4100  - http://erj.ersjournals.com/content/40/Suppl_56/P601.full
SO  - Eur Respir J2012 Sep 01; 40
AB  - Introduction: The 6MW is used to assess interventions in COPD but existing estimates of the MCID for have been derived from narrow cohorts where a non-blinded intervention, for example pulmonary rehabilitation, have been applied.Objective: To define the MCID for 6MW distance in an unselected population.Methods: Data from the ECLIPSE cohort were used. Briefly 2112 patients were prospectively followed for 3 years in a multicentre study. We defined an index event as death or first hospitalisation and calculated the change in 6MW (Δ6MW) in the last 12 month period before the event occurred. If a patient did not have an event the last 12 month change was used. We also related Δ6MW to commonly used outcome measures in COPD; FEV1 and St Georges Respiratory Questionnaire (SGRQ-C).Results: Of the subjects with Δ6MW, 94 patients died and 323 were hospitalised. 6MW fell by mean (SD) 29.7 (82.9)m more in those who died than survivors (p<0.001). No significant difference in Δ6MW was observed in those who had a first hospitalisation than those who did not. Cox proportional hazard modelling showed that a Δ6MW of more than –30m conferred a hazard ratio of 1.93 (95% CI: 1.29, 2.90; p=0.001) for death. Weak relationships only were observed between Δ6MW and ΔFEV1 or Δ SGRQ.Conclusions: A fall in 6MW of 30m or more is associated with increased risk of death in patients with COPD and therefore represents a clinically significant MCID for this test. The modest relationships between Δ6MW and ΔFEV1 or Δ SGRQ suggest that anchor based methods for determining MCID are context dependent.Funded by GSK (SCO104960; NCT00292552).