Abstract
Background
Recruitment to time and target in clinical trials is a key challenge requiring careful estimation of numbers of potential participants. The SCOPiC trial ((HTA 12/201/09) (ISRCTN75449581)) is investigating the clinical and cost-effectiveness of stratified care for patients with sciatica in primary care. Here, we describe the approaches followed to achieve recruitment of our required sample size (n=470), the challenges encountered and required adaptations.
Methods
We used recruitment data from the SCOPiC trial and its internal pilot, to show the differences between estimated and actual numbers of patients from consultation to participation in the trial. Patients were consented to the trial if they had a clinical diagnosis of sciatica (with at least 70% confidence) and met the trial eligibility criteria.
Results
Initial recruitment estimates suggested we needed a source population of 146,000 adults registered at approximately 30 GP practices, and a monthly trial recruitment target of 22 patients per month over 22 months. The internal pilot trial phase resulted in revisions of these estimates to 256,000 and 42 GP practices. To date, 1,623 patients have been screened for eligibility and 450 randomised. The main reason for ineligibility is low confidence in the diagnosis of sciatica.
Conclusion
Our experience highlights the challenge of recruitment to clinical trials of sciatica, particularly in terms of case definition, and the need for careful planning and an internal pilot phase prior to a main trial. We believe our experience will be helpful to others conducting trials with sciatica patients.
No conflicts of interest
Funding
NEF is an NIHR Senior Investigator. KK is supported through a HEFCE Senior Clinical Lecturer award. The SCOPiC trial is funded by the National Institute for Health Research Health Technology Assessment Programme (NIHR HTA project number 12/201/09). The views and opinions expressed therein are those of the authors and do not necessarily reflect those of the NIHR, NHS or the Department of Health
