<p>Simple standard equation for daily step count in Japanese patients with chronic obstructive pulmonary disease</p>

Abstract

Purpose 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.

Reference Equations for Assessing the Physical Activity of Japanese Patients with Chronic Obstructive Pulmonary Disease

“…In our previous report, which demonstrated a simple reference equation for step count, the age, IC, and mMRC were extracted as PA-related factors of the step count; 10 however, the 6MWD, HADS-A, FEV1 %pred, and mMRC were extracted in the current study. IC was not extracted as a PA-related factor, although it was reported to be more closely related to PA than FEV1.…”

“…We previously developed a simple reference equation for step count in Japanese patients with COPD using the age, IC, and mMRC. 10 However, PA in COPD can be influenced by many other factors. In the current study, we prospectively evaluated the influences of 28 total factors, as follows: exercise capacity, muscle strength, presence of medication for COPD, presence of pulmonary rehabilitation, presence of comorbidity, and types of comorbidities (eg anemia, diabetes mellitus, cardiac dysfunction, malnutrition, depression, and anxiety) in addition to demographic factors, the pulmonary function, and dyspnea.…”

“…To calculate the predictive PA value of an individual patient, we recently developed a simple reference equation for the step count in Japanese patients with COPD from a retrospective study using demographic factors, pulmonary function, and the dyspnea scale. 10 However, COPD was reported to be associated with many other factors aside from the pulmonary function or dyspnea. These factors include the exercise capacity, 11,12 nutritional disturbance, 13,14 diabetes mellitus, [15][16][17] anemia, 18,19 cardiovascular disease, 20,21 muscle weakness, 22,23 depression, 24,25 and anxiety [25][26][27] and may also influence PA in COPD.…”

A Non-Interventional, Cross-Sectional Study to Evaluate Factors Relating to Daily Step Counts and Physical Activity in Japanese Patients with Chronic Obstructive Pulmonary Disease: STEP COPD

“… 20 , 41 It has been shown that shortness of breath is particularly highly correlated with PA at ≥3 METs. 42 Assessments of mMRC are clinically important not only for understanding the severity of dyspnea but also for identifying patients who are at risk of reduced PA. The purpose of this study was to identify factors that affect the number of steps taken and the duration of PA at ≥2 METs and ≥3 METs.…”

Effects of Individualized Target Setting on Step Count in Japanese Patients with Chronic Obstructive Pulmonary Disease: A Pilot Study

“…We recently created a formula to determine the predicted step count (Pred) using parameters associated with the step count in COPD patients. This formula consists of age, mMRC, and inspiratory capacity (IC) [23], and reflects the disease condition of each patient.…”