Challenges in Recruitment to a Randomized Controlled Study of Cardiovascular Disease Reduction in Sleep Apnea: an Analysis of Alternative Strategies

Study Objectives: A challenge in conducting randomized controlled trials of sleep apnea is the timely recruitment of participants to active and control arms. This study assesses the costs and efficiencies of alternative recruitment methods.

Design: Analysis of recruitment data from the Best Apnea Intervention in Research planning study.

Setting: Sleep clinics and cardiology practices.

Participants: One hundred forty-eight individuals with an apnea-hypopnea index > 15 and cardiovascular (CV) risk factors randomized from a pool of more than 30,000 potentially eligible patients.

Interventions: Comparisons: (1) modes of recruitment: face-to-face (F2F) recruitment versus mail-based recruitment (MBR); (2) recruitment source (sleep versus cardiology clinics).

Measurements And Results: Recruitment yield was defined as the ratio of the number of subjects randomized to the number of screened records. Recruitment costs were estimated based on staff time. Of the 148 randomized subjects, 25 were recruited from sleep clinics using F2F recruitment and 123 were recruited from cardiology using a F2F (n = 35) or MBR (n = 88) strategy. F2F recruitment yields were 0.17% and 0.30% for sleep versus cardiology sources, respectively (P = 0.04). A comparison of F2F to MBR showed recruitment yields of 1.11% and 0.90% and costs per randomized subject of $2,139 and $647, respectively.

Conclusions: Large resources may be needed to meet the recruitment goals of sleep apnea intervention trials. Recruitment source and mode influence efficiencies. For a trial comparing active versus sham continuous positive airway pressure in patients with CV risk factors, recruiting from cardiology was more efficient than from sleep clinics. MBR was three times less costly than F2F recruitment.