Recruitment to clinical trials of exercise: challenges in the peripheral arterial disease population

To describe recruitment to a randomised controlled trial of a 12-week (twice-weekly) supervised exercise programme for patients with peripheral arterial disease (PAD). PAD is a chronic, progressive disease with a significant cardiovascular and cerebrovascular risk burden, and exercise is an effective primary management approach.

Potential patients were identified from the Non-Invasive Vascular Laboratory records and invited to participate in the study. On successful completion of an incremental treadmill exercise test, patients were allocated at random to a control (usual care) or an exercise group.

Between November 2006 and June 2009, 548 patients were identified. Of the 156 patients who met the inclusion criteria, 40 (26%) declined to participate. Of the 71 patients who underwent exercise testing, 23 (32%) did not complete the test. The final enrolment number was 44 (44/156; 28%). Eleven patients (11/28; 39%) subsequently withdrew from the exercise programme.

Recruitment to clinical trials of exercise presents significant challenges in the PAD population due to the presence of co-existing cardiovascular and cerebrovascular disease, a reluctance to exercise due to leg pain, and an acceptance of reduced mobility as part of ageing. Early identification in primary care before the onset of significant comorbidity may ameliorate some of these issues.