# Recruitment of Informal Caregivers of Persons with Dementia into Clinical Trial: The power of the Messenger

## TL;DR

Using a trusted messenger significantly improved recruitment rates for a dementia caregiver clinical trial compared to cold calls.

## Contribution

Demonstrates that leveraging preexisting relationships through a trusted messenger is vastly more effective for clinical trial recruitment.

## Key findings

- Trusted messenger recruitment had a 23.88% enrollment rate versus 1.18% for cold calls.
- Trusted messenger was 20 times more effective than cold calls in recruiting participants.
- Cold calls, though easier for researchers, yielded fewer enrollments per contact.

## Abstract

The success of a randomized controlled trial depends on the timely and effective recruitment of participants. We aimed to investigate the effect of a trusted messenger on the recruitment process into a randomized controlled trial testing the efficacy of a mobile caregiver intervention in reducing caregiver burden and patient behavioral and psychological symptoms of dementia (BPSD).

A total of n = 4630 potential participants were contacted. Recruitment occurred via (1) “Cold Call,” where patients from a health system registry were called by research staff, and (2) “trusted messenger,” where research staff called patients who were referred directly from a memory care physician. The outcome measure was the call-to-consent ratio. A two-population proportion Z-test compared the ratios between the two recruitment methods.

The enrollment rate was 23.88% for participants recruited via the “trusted messenger” method and 1.18% for those recruited from the “cold calls” method (z = 15.11, p ≈ 0.0000).

“Trusted Messenger” was 20 times more effective than “Cold Calls” in recruiting human subjects into a clinical trial. Trusted Messenger leverage preexisting relationship. Although “Cold calls” is perceived as easy for the researcher to complete, it yields fewer enrollments per points of contact. Future studies should examine and compare other recruitment methods among ethnically diverse samples such as community outreach, flyer posting, and door-to-door solicitation.