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Published on: November 26, 2015
Systematic bias introduced by the informed consent process in a diagnostic research study.
Alice M Mitchell1, Jeffrey A Kline
1Department of Emergency Medicine, Carolinas Medical Center, Charlotte, NC, USA.
Summary
Informed consent for emergency department studies can introduce bias. The written consent process may lead to underestimating disease prevalence, particularly venous thromboembolism (VTE), by excluding sicker patients or those hesitant to provide blood samples.
Area of Science:
- Emergency Medicine
- Clinical Research Methodology
- Biostatistics
Background:
- Informed consent is crucial in clinical research.
- Minimal-risk studies in emergency departments (EDs) face unique enrollment challenges.
- Potential biases in enrollment can affect study outcomes.
Purpose of the Study:
- To assess population characteristics of patients approached for consent in an ED study.
- To identify outcomes and reasons for unsuccessful enrollment.
- To evaluate the impact of the informed consent process on disease prevalence estimates.
Main Methods:
- Prospective enrollment of consecutive ED patients undergoing evaluation for pulmonary embolism (PE).
- Collection of written informed consent for blood sampling and follow-up.
- Recording of reasons for refusal to participate.
- Diagnosis of venous thromboembolism (VTE) using D-dimer testing and CT angiography.
Main Results:
- 91% of eligible patients were approached; consent was obtained from 64%.
- VTE prevalence was 6% in participants vs. 13% in nonparticipants.
- Nonparticipants were more likely to be African American, uninsured, or on Medicaid.
Conclusions:
- The written informed consent process can introduce significant bias into disease prevalence estimates.
- Enrollment bias may result from factors like medical acuity and reluctance to provide samples.
- Further research is needed to understand and mitigate consent-related biases in ED research.
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