Original ArticleTelephone reminders are effective in recruiting nonresponding patients to randomized controlled trials
Section snippets
Background
Recruiting participants to a randomized controlled trial (RCT) is often a demanding task. Important barriers to participation have been identified as added demands when participating, possible damage to the professional relationship, and concerns about the procedures of recruitment and consent [1]. The validity of any study rests on how representative the sample is, as any inference drawn applies only to the sample taking part in the study. An increase in uptake rate is expected to increase the
Design
The study design was a randomized controlled trial of a structured telephone follow-up versus no telephone follow-up to a recruitment letter into a community based trial.
Participants
Employees (age 16–66) sick-listed for more than 7 weeks due to nonsevere psychological problems or musculoskeletal pain were eligible (Table 1). Diagnosis was made according to the International Classification of Primary Care (ICPC). The ICPC has been used by Norwegian physicians since 1992 and has been shown to have acceptable
Results
A total of 703 persons received a letter informing them about the project. Among the recipients, 301 persons (42.8%) had musculoskeletal disorders, 323 (45.9%) had mental health problems, and 79 (11.2%) had various other diagnoses. Nearly half the sample (347) had only one episode of sick leave in the last 2 years; the others had two or more episodes in the last two years. Average age was 41.3 years. Characteristics of all participants are shown in Table 1.
Small differences were found between
Discussion
By phoning eligible persons who had not responded to a written invitation, we increased the number of additional subjects recruited to the RCT.
The strength of this study is that it was a randomized comparison with 100% follow-up for the main outcome, the number of persons recruited to an RCT. This illustrates the power of a well-designed RCT, with internal validity as high as possible; however, we believe that the results should be discussed regarding external validity.
The obvious solution to
Conclusions
The intention to recruit analysis revealed nonsignificant results.
Uptake among nonresponders was significantly increased by a simple telephone reminder, which suggests that such a reminder should be used whenever possible. Systematic use of telephone contact might be a very effective way to increase the uptake rate in RCTs. Recruiting a larger percentage of the population to the study sample might also add to the external validity of study results.
Acknowledgements
The authors thank the Royal Ministry of Social Affairs, Norway, for funding this study. This study could not have been done without the support and contributions of the representatives of the local social security offices. The project team and especially the phone follow-up coordinator, Hildegunn Waal, should be credited for their enthusiastic energy and empathetic approach.
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