Article

OBJECTIVE: To establish the minimal important difference (MID) for the six-minute
walk distance (6MWD) in persons with chronic obstructive pulmonary disease
(COPD). DESIGN: Analysis of data from an observational study using distribution-
and anchor-based methods to determine the MID in 6MWD. SETTING: Outpatient
pulmonary rehabilitation program at 2 teaching hospitals. PARTICIPANTS:
Seventy-five patients with COPD (44 men) in a stable clinical state with mean age
70 years (SD 9 y), forced expiratory volume in one second 52% (SD 21%) predicted
and baseline walking distance 359 meters (SD 104 m). INTERVENTIONS: Not
applicable. MAIN OUTCOME MEASURES: Participants completed the six-minute walk
test before and after a 7-week pulmonary rehabilitation program. Participants and
clinicians completed a global rating of change score while blinded to the change
in 6MWD. RESULTS: The mean change in 6MWD in participants who reported themselves
to be unchanged was 17.7 meters, compared with 60.2 meters in those who reported
small change and 78.4 meters in those who reported substantial change (P=.004).
Anchor-based methods identified an MID of 25 meters (95% confidence interval
20-61 m). There was excellent agreement with distribution-based methods
(25.5-26.5m, kappa=.95). A change in 6MWD of 14% compared with baseline also
represented a clinically important effect; this threshold was less sensitive than
for absolute change (sensitivity .70 vs .85). CONCLUSIONS: The MID for 6MWD in
COPD is 25 meters. Absolute change in 6MWD is a more sensitive indicator than
percentage change from baseline. These data support the use of 6MWD as a
patient-important outcome in research and clinical practice.
CI - Copyright 2010 American Congress of Rehabilitation Medicine. Published by
Elsevier Inc. All rights reserved.

Langue : ANGLAIS