Abstract
Cavalheri V, Hernandes NA, Camillo CA, Probst VS, Ramos D, Pitta F. Estimation of
maximal work rate based on the 6-minute walk test and fat-free mass in chronic obstructive
pulmonary disease.
Objective
To propose a predictive equation of the maximal work rate (Wmax) in patients with
chronic obstructive pulmonary disease (COPD) based on the product of 6-minute walking
test (6MWT) and fat-free mass (FFM) and to compare it with a previously proposed equation
based on the product of 6MWT and body weight (BW).
Design
Descriptive (cross-sectional) study.
Setting
University-based rehabilitation center.
Participants
Patients with COPD (N=53; 30 men; forced expiratory volume in 1 second, 45%±15% predicted).
Interventions
Not applicable.
Main Outcome Measures
Three Wmax were produced: Wmax_real (obtained from the maximal cycle ergometry test),
Wmax_BW (estimated from the product of 6MWT and BW), previously proposed by Hill et
al. (Arch Phys Med Rehabil 2008; 89(9):1782-7); and Wmax_FFM (estimated from the product of 6MWT and FFM).
Results
The equation derived from a regression model to estimate Wmax_FFM was as follows:
−27.9717+3.7792*(6MWT*FFM). Wmax_real correlated better with Wmax_FFM (r=.64) than with Wmax_BW (r=.54). There was no difference between Wmax_FFM (median [interquartile range], 41
[29–50] W) and Wmax_real (40 [20-50] W, P=.88), whereas Wmax_BW (60 [52–69] W) significantly overestimated Wmax_real (P<.0001).
Conclusions
In patients with COPD, Wmax is better estimated by an equation including the product
of 6MWT and FFM than by a previously proposed equation including the product of 6MWT
and body weight.
Key Words
List of Abbreviations:
6MWT (six-minute walk test), BMI (body mass index), BW (body weight), COPD (chronic obstructive pulmonary disease), FFM (fat-free mass), FFMI (fat-free mass index), ICC (intraclass correlation coefficient), Wmax (maximal work rate), Wmax_real (real maximal work rate)To read this article in full you will need to make a payment
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References
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Article info
Footnotes
Supported by the FAPESP (São Paulo Research Foundation, grant no. 2009/04246-9) and CNPq (National Council for Scientific and Technological Development, grant no. 470848/2007-3).
No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit on the authors or on any organization with which the authors are associated.
Identification
Copyright
© 2010 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.
