In veterans with COPD, pain highly prevalent and tied to lower exercise capacity

Among veterans with COPD, pain was highly prevalent and was significantly associated with lower exercise capacity, according to findings published in BMC Pulmonary Medicine.

“Three cross-sectional studies and one study with short-term follow-up have demonstrated an association between pain and decreased levels of physical activity and exercise capacity, as measured by the 6-minute walk test, among patients with COPD,” Rebecca A. Raphaely, MD, research fellow in the department of pulmonary and critical care medicine at the VA Boston Healthcare System, Massachusetts General Hospital and Beth Israel Deaconess Medical Center, and colleagues wrote. “There are no studies to date, however, evaluating these relationships with direct measures of physical activity in persons with COPD ready to engage in physical activity.”

The researchers performed a retrospective secondary analysis to assess three cohorts of 373 veterans with COPD (mean age, 70 years; 98% men) who participated in longitudinal studies that evaluated physical activity and exercise capacity via daily step counts and 6-minute walk test distance. All participants were aged at least 40 years and diagnosed with COPD based on a smoking history of 10 pack-years or more and had an FEV₁ to FVC ratio of 0.7 or less. Researchers assessed pain using the bodily pain domain of the Veterans RAND 36-item Health Survey. Participants were randomly assigned to a web-based pedometer-mediated physical activity intervention in two of the three cohorts (n = 111).

Overall, 311 (83%) participants reported at least mild and/or a little bit of interference due to pain at baseline. Greater bodily pain was associated with lower 6-minute walk test distance (beta = 0.51; 95% CI, 0.2-0.82; P = .0013). In addition, worsening bodily pain was associated with 6-minute walk test distance decline (beta = 0.3; 95% CI, 0.03-0.58; P = .0312).

Physical activity intervention was associated with an improvement in bodily pain scores (beta = 6.17; 95% CI, 1.84-10.45; P = .0054) compared with usual care.

Researchers observed no association between reported baseline bodily pain and reported baseline daily step counts among participants, baseline bodily pain and physical activity change or change in bodily pain and physical activity change.

“Our study demonstrates a high prevalence of pain and a significant association between pain and exercise capacity among patients with COPD interested in engaging in [physical activity]. A technology-based physical activity intervention may be a nonpharmacological treatment of pain,” the researchers wrote. “Identifying and treating pain should be routine parts of exercise counseling in COPD.”