Cardiovascular disease is among the most prevalent concomitant chronic diseases in COPD. Physical activity (PA) modifies endothelial function and is commonly impaired in COPD. However, studies directly investigating the effects of increased PA on endothelial function in COPD are lacking. We investigated the effect of changes in PA on endothelial function in patients with severe to very severe COPD. Furthermore, we determined which variables modify this effect.
This is a secondary outcome analysis from a randomised controlled trial investigating the effects of combined PA counselling and pedometer-based feedback in COPD. We analysed the change in PA based on three visits during one year. We measured PA using a validated triaxial accelerometer, and endothelial function using flow-mediated dilation.
Data was analysed from 54 patients, which provided 101 change scores. Multiple regression modelling, including adjustment for baseline step count, showed strong evidence for an association between changes in flow-mediated dilation and changes in PA (p < 0.001). The analysis of several effect modificators showed no evidence of any influence on the interaction between PA and endothelial function: smoking status (p = 0.766), severity of airflow obstruction (p = 0.838), exacerbation frequency (p = 0.227), lung diffusion capacity of carbon monoxide % pred. (p = 0.735).
We found strong evidence that increasing steps per day ameliorates the heavily impaired endothelial function in patients with severe and very severe COPD. Further studies should examine which factors influence this relationship in a positive or negative manner.

Copyright © 2020. Published by Elsevier Ltd.