An Analysis of Recruitment Efficiency for an End-of-Life Advance Care Planning Randomized Controlled Trial

Optimizing recruitment efficiency is an important strategy to address the resource limitations that typically constrain clinical research. Surprisingly, little empiric data exist to guide research teams attempting to recruit a difficult population into similar studies. Our objective was to investigate factors associated with enrollment into an advance care planning interventional trial.

This study used secondary data of patients with advanced cancer receiving treatment at an academic medical center in central Pennsylvania who were referred to a randomized controlled trial of an advance care planning intervention. Enrolled participants were compared to nonparticipants with regard to age, gender, race, season of recruitment, elapsed time between recruitment stage, distance to study site, and number of recruitment calls.

Of the 1988 patients referred, 200 participants were enrolled yielding a recruitment efficiency of 10%. Two-thirds of all enrolled participants were recruited with 1 or less phone calls, whereas only 5% were enrolled after 3 calls. There were no statistically significant differences in enrollment based on gender ( P = .88) or elapsed time between recruitment contacts ( P = .22). However, nonparticipants were slightly older ( P = .02).

Our finding that individuals were more likely to enroll within the first 3 phone calls suggests that recruitment efforts should be focused on making initial contacts with potential participants, rather than continuing attempts to those who are unable to be contacted easily. Researchers could optimize their recruitment strategy by periodically performing similar analyses, comparing differences between participants and nonparticipants.