One Year Change in 6-Minute Walk Test Outcomes is Associated with COPD Prognosis

Area of Science:

• Pulmonary Medicine
• Clinical Physiology
• Respiratory Research

Background:

• The six-minute walk test (6MWT) assesses functional capacity in chronic obstructive pulmonary disease (COPD).
• Desaturation and changes in 6-minute walk distance (6MWD) during 6MWT may predict COPD progression.
• Longitudinal data on these 6MWT parameters as risk factors are limited.

Purpose of the Study:

• To investigate if changes in 6MWD and desaturation status over one year predict mortality, lung function decline, and exacerbations in COPD patients.
• To identify specific 6MWT parameters indicative of increased risk in COPD.

Main Methods:

• A cohort of 295 COPD patients underwent 6MWT at baseline and one year later.
• Mortality data were collected from the Norwegian Cause of Death Registry.
• Cox regression, linear mixed-effect models, and negative binomial regression were used to analyze mortality, lung function (FVC, FEV1), and exacerbations, respectively.

Main Results:

• Patients with persistent desaturation during 6MWT showed significantly higher all-cause and respiratory mortality (HR 2.7 and 3.6).
• New-onset desaturation at year one also increased all-cause mortality risk (HR 2.0).
• Desaturation at year one was linked to accelerated decline in forced vital capacity (FVC) % predicted.

Conclusions:

• Repeated desaturation during 6MWT is a significant risk factor for mortality in COPD patients.
• The onset of desaturation during 6MWT is associated with future declines in lung function, particularly FVC.
• 6MWT desaturation status over time provides valuable prognostic information for COPD management.