Optimal Cut-Off Points of 4-meter Gait Speed to Discriminate Functional Exercise Capacity and Health Status in Older Patients with Chronic Obstructive Pulmonary Disease

Background: Gait speed, a vital sign of health and functional capacity, is commonly used to measure mobility. Although studies have assessed gait speed in older adults and individuals with chronic obstructive pulmonary disease (COPD) separately, few have evaluated gait speed in older adults with COPD. Therefore, the primary objective of our study was to determine the threshold point for the 4-meter gait speed test (4MGS) to better discriminate between functional exercise capacity and health status in older patients with COPD. The second objective was to determine possible predictors of gait speed.

Methods: In this cross-sectional study, we assessed participants' pulmonary function, dyspnea, health status (COPD Assessment Test [CAT]), gait speed (4MGS), functional exercise capacity (6-minute walk test [6MWT]), and physical activity.

Results: Forty-five older patients with COPD participated in this study. The predicted 6MWT and CAT scores were independent and significant determinants of the 4MGS score, explaining 54% of the variance (p<0.001). We identified gait speeds of 0.96 m/s and 1.04 m/s as thresholds to predict abnormal functional exercise capacity (sensitivity 85% and specificity 56%) and impaired health status (sensitivity 90% and specificity 69%), respectively (p<0.05).

Conclusion: Our findings demonstrated that gait speed can discriminate between abnormal functional exercise capacity and impaired health status in older patients with COPD. Moreover, functional exercise capacity and health status are predictors of gait speed.