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Differences in physical activity according to mMRC grade in patients with COPD

Authors Hayata A, Minakata Y, Matsunaga K, Nakanishi M, Yamamoto N

Received 1 April 2016

Accepted for publication 3 June 2016

Published 13 September 2016 Volume 2016:11(1) Pages 2203—2208


Checked for plagiarism Yes

Review by Single-blind

Peer reviewers approved by Dr Charles Downs

Peer reviewer comments 4

Editor who approved publication: Dr Richard Russell

Atsushi Hayata,1 Yoshiaki Minakata,2 Kazuto Matsunaga,3 Masanori Nakanishi,1 Nobuyuki Yamamoto1

1Third Department of Internal Medicine, Wakayama Medical University, School of Medicine, Wakayama, 2Department of Respiratory Medicine, National Hospital Organization Wakayama Hospital, Wakayama, 3Department of Respiratory Medicine and Infectious Disease, Graduate School of Medicine, Yamaguchi University, Yamaguchi, Japan

Background: Physical activity (PA) is impaired from the early stages of COPD, is associated with a worsening of disease prognosis, and causes COPD patients to restrict their daily activities in order to avoid breathlessness. The development of a simple tool to estimate physical activity level (PAL) could be useful for the management of COPD.
Objectives: We investigated the differences in PA according to the modified Medical Research Council (mMRC) grade in patients with COPD.
Methods: A cross-sectional study was performed on stable outpatients with COPD. PA was measured for 2 weeks using a triaxial accelerometer, and dyspnea grade was evaluated in all patients using the mMRC scale.
Results: Ninety-eight patients were recruited. Significant differences in PA duration were observed at all intensities according to the mMRC grade. Despite treatment with controller medications, 59.2% of COPD patients had low PAL, which was <1.5 metabolic equivalents multiplied by hour per day. COPD patients with an mMRC grade ≥2, which was the most balanced cutoff point in the receiver operating characteristic curve, showed a higher reduction rate of PAL (80.0% at mMRC grade 2, 71.4% at mMRC grade 3, and 100% at mMRC grade 4).
Conclusion: PA differed according to the mMRC grade, and mMRC grade ≥2 could predict a low PAL. Therefore, assessment of breathlessness by the mMRC questionnaire would be useful to stratify the risks of reduced PA in COPD.

accelerometer, questionnaire, dyspnea, METs

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