4.

BACKGROUND:Measures of physical function, daily physical activity, and exercise capacity have been proposed for the care of patients with COPD but are not used routinely in daily offi ce care. Gait speed is a powerful and simple measure of physical function in elderly patients and seems to be a promising measure for the daily care of patients with COPD. Th e objective of this study was to comprehensively evaluate the determinants and factors infl uencing gait speed in COPD, particularly the association of gait speed with objectively measured physical activity and the most used exercise capacity fi eld test in cardiopulmonary disease: the 6-min walk test (6MWT).

BACKGROUND: Gait speed is a simple physical function measure associated with key outcomes in the elderly population. Gait speed measurements may improve clinical care in patients with COPD. However, there is a knowledge gap about the reliability and variability of gait speed testing protocols in COPD. We evaluated established techniques of measuring gait speed in patients with COPD and assessed feasibility of implementing gait speed as a routine vital sign in an out-patient clinic. METHODS: The usual 4-meter gait speed (4MGS) ("walk at a comfortable/natural pace"), maximal 4MGS ("walk as fast as you can safely"), usual 10-meter gait speed (10MGS), and maximal 10MGS of subjects with stable COPD were measured. Walks were measured using a stopwatch and automated timing system. For the feasibility/implementation phase, patients from the entire spectrum of respiratory diseases completed acceptability surveys, and clinical assistants administered gait speed measurements using an automated timing system. Time to train and to administer the test and acceptability by the staff were evaluated. RESULTS: Seventy subjects enrolled; 60% were men, and the mean age ؎ SD was 69 ؎ 10 years. All methods showed excellent test-retest reliability (intraclass correlation coefficient of 0.95-0.97). The difference between the two timing systems did not exceed the suggested minimal clinically important difference of 0.1 m/s for the usual pace instructions but did exceed 0.1 m/s for maximal pace walks. The difference between 4MGS and 10MGS was 0.13 ؎ 0.10 m/s. FEASIBILITY: Most subjects reported that gait speed measurement prior to clinic appointment was very acceptable (66%) or acceptable (33%). Time added to clinic visit measuring 4MGS was 95 ؎ 20 seconds, and clinical assistants reported gait speed measurements as very acceptable (60%), acceptable (30%), and somewhat acceptable (10%). CONCLU-SIONS: Gait speed is a reliable measure in COPD, regardless of instructed pace, distance, or timing mechanism; however, adhering to one protocol is suggested. 4MGS was easily implemented into clinical practice with high acceptability by patients and clinic staff.

BACKGROUND Four-meter gait speed (4MGS) has been associated with functional capacity and overall mortality in elderly patients, and may easily be translated to daily practice. We evaluated the association of 4MGS with meaningful outcomes. METHODS In 70 subjects we conducted the 4MGS, 6-min walk test (6MWT), objectively measured physical activity, and assessed dyspnea, quality of life, and self-efficacy for walking and routine physical activity. 4MGS was measured in 3 separate time epochs during the 6MWT, to explore 4MGS variability. RESULTS Diagnoses included COPD (51.4%), interstitial lung disease (38.6%), and other pulmonary conditions (10%). The mean ± SD values were: 4MGS 0.85 ± 0.21 m/s, 6-min walk distance (6MWD) 305 ± 115 m, and physical activity level 1.28 ± 0.17, which is consistent with severe physical inactivity. The gait speeds within the time epochs 1–2, 3–4, and 5–6 min during the 6MWT were not significantly different: 1.01 ± 0.29 m/s, 0.98 ± 0.31 m/s, and 1.00 ± 0.31 m/s, respectively. 4MGS had a significant correlation with 6MWD (r = 0.70, P < .001). 6MWD was the dominant variable for predicting 4MGS. Other significant predictors of 4MGS included dyspnea, self-efficacy, quality of life, and objectively measured physical activity. CONCLUSIONS 4MGS is significantly and independently associated with 6MWD, and may serve as a reasonable simple surrogate for 6MWD in subjects with chronic lung disease. Gait speed was remarkably stable throughout the 6MWT, which supports the validity of an abbreviated walk test such as 4MGS.

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