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Reporting methods of blinding in randomized trials assessing nonpharmacological treatments
Isabelle Boutron1, Lydia Guittet, Candice Estellat
1INSERM, U738, Paris, France. isabelle.boutron@bch.ap-hop-paris.fr
Background:
Blinding is a cornerstone of treatment evaluation. Blinding is more difficult to obtain in trials assessing nonpharmacological treatment and frequently relies on "creative" (nonstandard) methods. The purpose of this study was to systematically describe the strategies used to obtain blinding in a sample of randomized controlled trials of nonpharmacological treatment.
Methods And Findings:
We systematically searched in Medline and the Cochrane Methodology Register for randomized controlled trials (RCTs) assessing nonpharmacological treatment with blinding, published during 2004 in high-impact-factor journals. Data were extracted using a standardized extraction form. We identified 145 articles, with the method of blinding described in 123 of the reports. Methods of blinding of participants and/or health care providers and/or other caregivers concerned mainly use of sham procedures such as simulation of surgical procedures, similar attention-control interventions, or a placebo with a different mode of administration for rehabilitation or psychotherapy. Trials assessing devices reported various placebo interventions such as use of sham prosthesis, identical apparatus (e.g., identical but inactivated machine or use of activated machine with a barrier to block the treatment), or simulation of using a device. Blinding participants to the study hypothesis was also an important method of blinding. The methods reported for blinding outcome assessors relied mainly on centralized assessment of paraclinical examinations, clinical examinations (i.e., use of video, audiotape, photography), or adjudications of clinical events.
Conclusions:
This study classifies blinding methods and provides a detailed description of methods that could overcome some barriers of blinding in clinical trials assessing nonpharmacological treatment, and provides information for readers assessing the quality of results of such trials.
Insights
Blinding in nonpharmacological treatment trials is challenging but achievable. This study details creative blinding methods for participants, caregivers, and assessors in randomized controlled trials.
Area of Science:
- Clinical Trials Methodology
- Evidence-Based Practice
- Health Research Evaluation
Background:
- Blinding is crucial for unbiased treatment evaluation in clinical trials.
- Achieving effective blinding is particularly challenging for nonpharmacological interventions.
- Creative and nonstandard methods are often employed to ensure blinding.
Purpose of the Study:
- To systematically describe the diverse strategies used for blinding in randomized controlled trials (RCTs) of nonpharmacological treatments.
- To provide a classification of blinding methods applicable to nonpharmacological interventions.
- To inform researchers and readers on assessing the quality of blinding in such studies.
Main Methods:
- Systematic search of Medline and Cochrane Methodology Register for RCTs published in 2004.
- Data extraction using a standardized form to identify and categorize blinding techniques.
- Analysis of 145 identified articles, focusing on the 123 that described blinding methods.
Main Results:
- Sham procedures (e.g., simulated surgery, attention controls, placebo administration) were common for participants and providers.
- Device trials utilized placebo interventions like sham prostheses or inactivated/shielded apparatus.
- Blinding outcome assessors involved centralized review of examinations (paraclinical, clinical via video/audio) and event adjudication.
Conclusions:
- This study offers a classification of blinding methods for nonpharmacological trials.
- Detailed descriptions of these methods can help overcome blinding barriers.
- The findings aid in evaluating the quality and reliability of results from nonpharmacological intervention studies.
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