Processing of Sedentary Time and Its Reference Equation in Patients with COPD

Area of Science:

• Pulmonary Medicine
• Biomedical Engineering
• Gerontology

Background:

• Sedentary time (ST) is an independent mortality risk factor in COPD patients.
• Optimal methods for processing accelerometric ST data and identifying related factors are not well-defined.

Purpose of the Study:

• To determine optimal processing conditions for accelerometric ST data in COPD.
• To identify factors associated with ST in COPD patients.
• To develop a reference equation for ST assessment in COPD.

Main Methods:

• Study 1: Evaluated data processing (minimum days for repeatability, effect of weather/weekends) in 38 COPD patients.
• Study 2: Identified ST-related factors (from 28 parameters) and developed a reference equation in 216 COPD patients.
• Validated the equation for patients with ST >= 6 hours.

Main Results:

• Minimum days for ST repeatability: 3 days (8-hr wear) and 2 days (10-hr wear).
• ST was significantly longer on rainy days, but not weekends.
• BMI, FEV1%pred, 6MWD, and mMRC were identified as key ST-related factors.

Conclusions:

• Properly processed ST data and a validated reference equation can aid in assessing ST in COPD patients.
• This tool is expected to facilitate personalized guidance for reducing sedentary time in COPD.