Bah humbug! Association between sending Christmas cards to trial participants and trial retention: randomised study within a trial conducted simultaneously across eight host trials.

ABSTRACT:

Objectives

To determine the effectiveness of sending Christmas cards to participants in randomised controlled trials to increase retention rate at follow-ups, and to explore the feasibility of doing a study within a trial (SWAT) across multiple host trials simultaneously.

Design

Randomised SWAT conducted simultaneously across eight host trials.

Setting

Eight randomised controlled trials researching various areas including surgery and smoking cessation.

Participants

3223 trial participants who were still due at least one follow-up from their host randomised controlled trial.

Intervention

Participants were randomised (1:1, separately by each host trial) to either received a Christmas card in mid-December 2019 or to not receive a card.

Main outcome measu

SUBMITTER: Coleman E 

PROVIDER: S-EPMC8669570 | biostudies-literature | 2021 Dec

REPOSITORIES: biostudies-literature