Prognostic Value of Gait Speed for Exacerbations and Mortality in COPD

Background Gait speed, a key component of exercise capacity, has been underutilized in chronic obstructive pulmonary disease (COPD), despite its prognostic potential. To evaluate the association between gait speed and clinical outcomes in COPD using three-year longitudinal data from the Korean COPD Subgroup Study cohort. Methods Poor gait speed (<1.0 m·s −1 ) was defined by usual pace during the six-minute walk test per Asian Working Group for Sarcopenia 2019 criteria. Lung function, symptoms, acute exacerbations (AEs), and mortality were compared between gait speed groups. Analyses included propensity score matching, quartile classification, subgroup analyses, and longitudinal trajectory modeling using random coefficient models. Results Among 2063 participants, poor gait speed (n=831, 40.3%) was associated with older age, higher symptom burden, and more prior AEs despite similar lung function. This group showed higher AE risk and frequency than the normal speed group: adjusted odds ratios 1.37–1.45 for moderate and 1.64–1.65 for severe AEs; adjusted incidence rate ratios 1.24–1.36 for moderate and 1.63–1.86 for severe AEs. Three-year mortality was significantly higher in the poor gait speed group (adjusted hazard ratio 2.30 [95% CI, 1.42–3.73]). Longitudinally, poor gait speed group demonstrated persistently worse CAT and SGRQ-C scores at baseline, with modest CAT worsening over time (+0.44 point/year, p=0.01), while lung function decline was similar. Conclusions Gait speed provides a simple, integrative marker that independently predicts exacerbation risk, mortality, and symptom progression in COPD.