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A rapid review indicated higher recruitment rates in treatment trials than in prevention trials

Cindy L Cooper1, Daniel Hind1, Rosie Duncan2

  • 1The School of Health and Related Research (ScHARR), Clinical Trials Research Unit, University of Sheffield, Regent Court, 30 Regent Street, Sheffield, S1 4DA, UK.

Journal of Clinical Epidemiology
|December 10, 2014
PubMed
Abstract

Insights

Prevention trials for type 2 diabetes recruit a smaller proportion of screened patients than treatment trials. This finding supports the hypothesis that trial design impacts patient recruitment rates for metformin and exercise interventions.

Area of Science:

  • Clinical Trials
  • Diabetes Research
  • Public Health

Background:

  • Recruitment is a critical phase in clinical trials.
  • Understanding factors influencing patient randomization is essential for trial efficiency.
  • Previous research has not clearly delineated recruitment differences between prevention and treatment trials.

Purpose of the Study:

  • To investigate whether the percentage of screened patients who randomize differs between prevention and treatment trials for type 2 diabetes.
  • To compare recruitment rates in trials evaluating metformin and exercise interventions.

Main Methods:

  • A rapid review of randomized controlled trials (RCTs) was conducted using published systematic reviews.
  • Data from 66 RCTs on metformin or exercise for type 2 diabetes prevention or treatment were analyzed.
  • The percentage of screened patients who were randomized was calculated and pooled across studies.

Main Results:

  • Metformin prevention trials randomized 6.2% of screened patients, while treatment trials randomized 50.7%.
  • Exercise prevention trials randomized 4.8% of screened patients, compared to 43.3% in treatment trials.
  • Significant statistical heterogeneity was observed in pooled estimates.

Conclusions:

  • The study provides evidence that prevention trials recruit a lower proportion of screened individuals than treatment trials.
  • These findings suggest that trial objectives (prevention vs. treatment) influence patient recruitment success.
  • Limitations including statistical heterogeneity warrant cautious interpretation of the pooled results.
Keywords:
Consent ratesEligibilityExercisePreventionRCTsRecruitment ratesScreening failuresTreatment

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