Repeated attempts using different strategies are important for timely contact with study participants

To study the effect of different mail- and phone-based strategies, along with patient- and research-related factors, on the time to contact with research participants.

A prospective evaluation of a 12-week standardized protocol (embedded with two randomized trials of mail- and phone-based strategies) for contacting existing research participants for recruitment into a related study.

Of 146 participants, 87 were eligible for contact via the standardized protocol, and 63 (72%) of these were successfully contacted within 12 weeks after multiple mail- and phone-based efforts. Using Cox proportional hazards regression analysis, the different mail and phone strategies showed no significant difference in the time to contact with participants. Of 34 patient- and research-related factors evaluated, only two were independently associated with time to contact among all 146 participants: (1) participants having their last visit conducted outside of the research clinic because of patient illness/condition had a longer time to contact and (2) those with a self-reported chronic fatigue history had a shorter time to contact.

Few patient characteristics and research-related factors accurately predict time to contact. Repeated attempts using different strategies are important for successful and timely contact with study participants.