Gait characteristics and their associations with clinical outcomes in patients with chronic obstructive pulmonary disease

Background: Abnormalities of spatiotemporal gait parameters are frequently observed in chronic obstructive pulmonary disease (COPD). However, associations of gait parameters with clinical outcomes and their implementation into clinical practice have not been established. Research question: To investigate gait abnormalities and their association with clinical outcomes of COPD. Methods: This study included 34 male outpatients with COPD and 16 community-dwelling healthy men aged >= 65 years. The subjects underwent a ten-metre walk test wearing an accelerometer. Data on gait speed, step length, cadence, walk ratio, acceleration magnitude, and standard deviation of step time (step time SD) were collected. Forced expiratory volume in 1-second, modified Medical Research Council dyspnoea score, six-minute walk distance (6MWD), quadriceps muscle strength (QMVC), and physical activity (daily steps and time spent in moderate to vigorous physical activity per day) were measured in the COPD group as clinical outcomes of COPD. We tested group differences in gait parameters, associations between gait parameters and COPD clinical outcomes, and predictive capability of gait parameters for reductions in 6MWD, QMVC, and daily steps in COPD. Results: All gait parameters except walk ratio deteriorated in COPD. Step time SD and gait speed were significant independent predictors of 6MWD in COPD (B = -0.440, p = 0.001, B = 0.339, p = 0.007, respectively). Step length was a significant independent predictor of QMVC (B = -0.609, p < 0.001) and daily steps (B = -0.453, p = 0.006). Step length was a significant predictor of muscle weakness and physical inactivity, and step time SD was significant in predicting poor 6MWD in COPD. Significance: Significant associations between gait abnormalities measured by an accelerometer and deficits in extra-pulmonary features of COPD were observed. An accelerometer-based gait analysis could be an alternative approach to assessing gait abnormalities and screening of functional decline in COPD.