COPD Mortality Risk and Physical Activity Have Dose-Response Relationship

Physical activity has a dose-response association with all-cause and cardiovascular disease (CVD) mortality risk in individuals with chronic obstructive pulmonary disease (COPD), according to a study published in BMC Public Health. In addition, protective effects occurred at levels considerably lower than general physical activity recommendations.

The investigators identified 2398 individuals with COPD aged 40 years or older from the 1997 Health Survey for England and the 1998 and 2003 Scottish Health Survey cohorts and followed them for a mean 8.5 years.

Self-reported total physical activity, moderate-vigorous intensity physical activity, walking, domestic physical activity, and sport/exercise were assessed at baseline. Associations between physical activity and mortality risk were assessed using Cox proportional hazards models.

For both total physical activity and moderate-vigorous intensity physical activity, the investigators observed linear dose-response associations with all-cause and CVD mortality risk, and to a lesser extent, with respiratory mortality risk. Individuals who met the physical activity guidelines experienced the greatest reductions in all-cause (hazard ratio [HR], 0.56; 95% CI, 0.45-0.69), CVD (HR, 0.48; 95% CI, 0.32-0.71), and respiratory mortality risk (HR, 0.40; 95% CI, 0.24-0.67) compared with those who reported no physical activity.

Those who achieved a level of physical activity of at least half the amount recommended by the guidelines also had a reduced risk for all-cause (HR, 0.75; 95% CI, 0.56-1.00) and CVD (HR, 0.48; 95% CI, 0.26-0.88) mortality. Dose-response associations with mortality risk were found for walking and sport/exercise, but not for domestic physical activity.

The authors noted that engaging in physical activity above a threshold of 3.75 metabolic equivalent-hours per week is still associated with significant reductions in mortality risk. They recommended that walking and structured exercise be encouraged for people with COPD.

Several study limitations were noted by the authors, including the use of a fixed forced expiratory volume in 1 second/forced vital capacity ratio to identify participants with COPD because of a lack of other information that may have helped confirm a diagnosis as well as possible misclassification of the physical activity variables because they were self-reported.

Reference

Cheng SWM, McKeough Z, Alison J, Dennis S, Hamer M, Stamatakis E. Associations of total and type-specific physical activity with mortality in chronic obstructive pulmonary disease: a population-based cohort study. BMC Public Health. 2018;18:268.