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The external validity of published randomized controlled trials in primary care
Ritu Jones1, Robert O Jones, Colin McCowan
1University of Dundee, UK. ritujones@gmail.com
BMC Family Practice
|January 21, 2009
Summary
Primary care Randomized Controlled Trials (RCTs) often lack participant representativeness. While most RCTs report recruitment numbers, a minority lack sufficient data, potentially impacting external validity.
Area of Science:
- Clinical Research Methodology
- Public Health
- Epidemiology
Background:
- Randomized Controlled Trials (RCTs) in primary care face criticism regarding external validity due to unrepresentative participant samples.
- This study investigates the reporting of participant recruitment processes in primary care RCTs.
Purpose of the Study:
- To determine if published primary care RCTs report how study samples are assembled.
- To assess associations between recruitment reporting and other RCT characteristics.
Main Methods:
- A review of RCTs published in four primary care journals between 2001 and 2004.
- Key metrics included eligibility fraction, enrolment fraction, recruitment fraction, and number of patients needed to screen (NNS).
Main Results:
- 148 RCTs were reviewed; 70% reported eligibility assessments, 80% reported eligible numbers, and all reported recruited numbers.
- Median eligibility fraction was 83%, and median enrolment fraction was 74%. Median NNS was 2.43.
- No association was found between NNS and journal, trial size, center type, funding, or intervention type, though some associations with recruitment data provision may exist.
Conclusions:
- Primary care RCTs suggest patients meeting eligibility criteria are likely randomized, but this may be due to inadequate reporting.
- A significant number of RCTs do not provide adequate data on the patient recruitment process.
- Further investigation into reporting standards for RCT recruitment is warranted to enhance external validity.
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