Four-meter gait speed (4MGS) is an independent risk factor for both 1-year all-cause readmission and mortality in patients with acute exacerbations of chronic obstructive pulmonary disease (COPD), according to the authors of a UK multicenter study published in the European Respiratory Journal.
As the investigators emphasized, “[t]here is growing interest in the prognostic role of simple functional tests in COPD as deterioration in functional capacity represents a common pathway that integrates multisystem consequences of the disease.”
“The 4MGS test, a measure of a patient’s usual walking speed, has been widely used as a surrogate marker of frailty in older adults . . . and has prognostic value in stable chronic respiratory conditions like COPD,” they wrote.
Noting that slower walking speed is associated with increased length of hospital admission and greater risk of a hospitalized older adult not being discharged home, the authors said the goal of their current study, a planned secondary analysis of a prospective cohort study (ClinicalTrials.gov Identifier: NCT01507415), was “to evaluate the ability of 4MGS to independently predict prognosis in AECOPD.”
Results from the 4MGS test performed at hospital discharge were examined for associations with outcomes prospectively observed for a period of 1 year. Outcomes of interest included all-cause readmission and mortality 1 year after discharge.
Among the 213 patients hospitalized with acute exacerbations of COPD for whom baseline data were collected, the mean age was 72 years, 52% were male, and mean forced expiratory volume in 1 second (FEV1) was 35% predicted. The investigators stratified participants into quartiles based on their 4MGS results: Q1, <0.40 meters per second; Q2, 0.4-0.59 meters per second; Q3, 0.60-0.79 meters per second; and Q4, 0.80 meters per second or greater. They used Kaplan-Meier analysis and log-rank testing to compare time to all-cause readmission and mortality between gait speed quartiles.
During the follow-up period, 111 participants were readmitted, and 35 participants died. Hospital readmission risk over 1 year decreased with increasing 4MGS at hospital discharge: 70% of patients in Q1 (slowest walkers) were readmitted, compared with 60% in Q2, 48% in Q3, and 29% in Q4 (fastest walkers) (P =.001). Risk of death over 1 year also decreased with increasing 4MGS, ranging from 32% of patients in Q1 to 4% of patients in Q4 (P <.001)
When outcomes were paired with results of the 4MGS test, all-cause readmission was associated with an adjusted subdistribution hazard ratio (HR) of 0.868 (P =.001) per 0.1 meter per second increase in gait speed, while all-cause mortality was associated with an adjusted subdistribution HR of 0.747 (P =.002) per 0.1 meter per second increase in gait speed. In addition, the authors reported that their readmission and mortality models incorporating 4MGS “had higher discrimination than age or FEV1 % predicted alone.”
The investigators concluded that study “4MGS is an independent risk factor for both 1-year all-cause readmission and mortality,” adding that since “the measure is simple, cheap, and quick, we propose that routine measurement at hospital discharge would provide clinicians with valuable information to plan post-discharge care and support.”
Disclosure: Several study authors declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.
Walsh JA, Barker RE, Kon SSC, et al. Gait speed and adverse outcomes following hospitalised exacerbation of COPD. Published online ahead of print April 29, 2021. Eur Respir J. 2021;2004047. doi:10.1183/13993003.04047-2020