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Presentation of continuous outcomes in randomised trials: an observational study
David L Schriger1, Dan F Savage, Douglas G Altman
1School of Medicine, University of California, Los Angeles, 924 Westwood Blvd. Los Angeles, CA 90024-2924, USA. schriger@ucla.edu
BMJ (Clinical Research Ed.)
|December 20, 2012
Summary
Randomized clinical trials report only a small fraction of available data for continuous outcomes. This incomplete reporting may increase the risk of bias in study findings.
Area of Science:
- Medical Research Methodology
- Clinical Trial Reporting Standards
- Biostatistics
Background:
- Incomplete reporting of data in randomized clinical trials (RCTs) can lead to biased interpretations of study findings.
- Assessing the extent of data reporting is crucial for understanding potential biases in medical literature.
Purpose of the Study:
- To quantify the percentage of available outcome data presented in RCT reports with continuous outcomes.
- To evaluate the potential for incomplete reporting bias in published RCTs.
Main Methods:
- A descriptive, cross-sectional study analyzed 200 RCTs published in 20 medical journals (2007-2009).
- The fraction of reported data for the primary continuous outcome was calculated using scoring rules, considering elements like sample size, means, and standard deviations.
- Compliance with the Consolidated Standards of Reporting Trials (CONSORT) statement was also assessed.
Main Results:
- The median percentage of available data reported for continuous outcomes was 9% (IQR: 3-26%), and 3.5% (IQR: 3-7%) when adjusted for study size.
- Only 17% of articles reported 100% of the data.
- While tables were common for data presentation, figures conveyed a higher proportion of data.
Conclusions:
- Trialists report a limited proportion of the data collected for continuous outcomes.
- This incomplete data presentation raises concerns about the potential for incomplete reporting bias in the medical literature.
- Findings highlight the need for improved data transparency in RCT reporting.
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