International Journal of COPD (Aug 2019)

Simple standard equation for daily step count in Japanese patients with chronic obstructive pulmonary disease

  • Nakanishi M,
  • Minakata Y,
  • Tanaka R,
  • Sugiura H,
  • Kuroda H,
  • Yoshida M,
  • Yamamoto N

Journal volume & issue
Vol. Volume 14
pp. 1967 – 1977

Abstract

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Masanori Nakanishi,1 Yoshiaki Minakata,2 Rie Tanaka,3 Hisatoshi Sugiura,3 Hikaru Kuroda,4 Makoto Yoshida,5 Nobuyuki Yamamoto11Third Department of Internal Medicine, Wakayama Medical University, Wakayama, Japan; 2Department of Respiratory Medicine, National Hospital Organization Wakayama Hospital, Wakayama, Japan; 3Department of Respiratory Medicine, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan; 4Department of Respiratory Medicine, National Hospital Organization Asahikawa Medical Center, Asahikawa, Hokkaido, Japan; 5Department of Respiratory Medicine, National Hospital Organization Fukuoka Hospital, Fukuoka, JapanCorrespondence: Yoshiaki MinakataDepartment of Respiratory Medicine, National Hospital Organization Wakayama Hospital, 1138 Wada Mihama-cho, Hidaka-gun, Wakayama 644-0044, JapanTel +81 73 822 3256Fax +81 73 822 2126Email [email protected]: The improvement of physical activity in patients with COPD is an important issue. However, no standard for the recommended number of steps for patients with COPD has been determined. We conducted a retrospective observational study to create a simple standard equation for the daily step count, which makes it easier to determine whether each subject is attaining his/her predicted value or not.Patients and methods: Stable outpatients diagnosed with COPD whose physical activities had been measured using a triaxial accelerometer for more than 2 weeks were recruited from 5 institutes in Japan. Factors associated with the step count were detected by multivariate regression analysis. After the data were transformed to a normalized distribution, a multivariate linear regression equation was created using stepwise regression.Results: One hundred sixty-two patients aged 72.3 (7.2) years and of FEV1 %pred 59.2 (22.8) % were recruited. Among the parameters, age, mMRC dyspnea scale and inspiratory capacity (IC) were detected by the stepwise method. The created standard equation was “Step count = (−0.079×[age]−1.595×[mMRC]+2.078×[IC]+18.149)3,”. The correlations between the calculated values and the measured values were observed, and fixed, and proportional biases between them were also observed. When patients with <6500 steps/day were selected, no systematic bias between them could be detected.Conclusion: A simple standard equation for Japanese patients with COPD was created using age, mMRC and IC, and could provide an individual-predicted value, especially for patients with <6500 steps/day.Keywords: COPD, physical activity, behavior modification, goal setting, accelerometer

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