Retrospective analysis of exercise capacity in patients with coronary artery disease after percutaneous coronary intervention or coronary artery bypass graft.

All data came from one cardiac rehabilitation centre, so results may not apply to other hospitals or patients who were not referred. It was retrospective, using records already available, and some comorbidities that can lower exercise capacity, such as peripheral vascular disease, obstructive lung disease or arthritis, were not captured. Only 7 patients had normal exercise capacity, so comparisons with that group are unstable. No treatment was tested, so the anxiety finding is an association and cannot show that anxiety causes low capacity or that anxiety treatment improves capacity. Anxiety and depression were measured by self-report questionnaires, not clinical diagnosis.

The study received no public, commercial or non-profit funding, and the authors declared no conflicts of interest.

Do not conclude that treating anxiety will improve exercise capacity. The study was retrospective and only found an association between higher anxiety scores and lower measured exercise capacity; no anxiety treatment was tested.