Differences in Reporting of Analyses in Internal Company Documents Versus Published Trial Reports: Comparisons in Industry-Sponsored Trials in Off-Label Uses of Gabapentin
To be credible, published research must present an unbiased, transparent, and accurate description of the study methods and findings so that readers can assess all relevant information to make informed decisions about the impact of any conclusions. Therefore, research publications should conform to universally adopted guidelines and checklists. Studies to establish whether a treatment is effective, termed randomized controlled trials (RCTs), are checked against a comprehensive set of guidelines: The robustness of trial protocols are measured through the Standard Protocol Items for Randomized Trials (SPIRIT), and the Consolidated Standards of Reporting Trials (CONSORT) statement (which was constructed and agreed by a meeting of journal editors in 1996, and has been updated over the years) includes a 25-point checklist that covers all of the key points in reporting RCTs.
Why Was This Study Done?
Although the CONSORT statement has helped improve transparency in the reporting of the methods and findings from RCTs, the statement does not define how certain types of analyses should be conducted and which patients should be included in the analyses, for example, in an intention-to-treat analysis (in which all participants are included in the data analysis of the group to which they were assigned, whether or not they completed the intervention given to the group). So in this study, the researchers used internal company documents released in the course of litigation against the pharmaceutical company Pfizer regarding the drug gabapentin, to compare between the internal and published reports the reporting of the numbers of participants, the description of the types of analyses, and the definitions of each type of analysis. The reports involved studies of gabapentin used for medical reasons not approved for marketing by the US Food and Drug Administration, known as “off-label” uses.
What Did the Researchers Do and Find?
The researchers identified trials sponsored by Pfizer relating to four off-label uses of gabapentin and examined the internal company protocols, statistical analysis plans, research reports, and the main publications related to each trial. The researchers then compared the numbers of participants randomized and analyzed for the main (primary) outcome and the type of analysis for efficacy and safety in both the internal research report and the trial publication. The researchers identified 21 trials, 11 of which were published RCTs that had the associated documents necessary for comparison.
The researchers found that in three out of ten trials there were differences in the internal research report and the main publication regarding the number of randomized participants. Furthermore, in six out of ten trials, the researchers were unable to compare the internal research report with the main publication for the number of participants analyzed for efficacy, because the research report either did not describe the primary outcome or did not describe the type of analysis. Overall, the researchers found that seven different types of efficacy analyses were described in the protocols, statistical analysis plans, and publications, including intention-to-treat analysis. However, the protocol or publication used six different descriptions for the intention-to-treat analysis, resulting in several important differences between the internal and published documents about the number of patients included in the analysis.
What Do These Findings Mean?
These findings from a sample of industry-sponsored trials on the off-label use of gabapentin suggest that when compared to the internal research reports, the trial publications did not always accurately reflect what was actually done in the trial. Therefore, the trial publication could not be considered to be an accurate and transparent record of the numbers of participants randomized and analyzed for efficacy. These findings support the need for further revisions of the CONSORT statement, such as including explicit statements about the criteria used to define each type of analysis and the numbers of participants excluded from each type of analysis. Further guidance is also needed to ensure consistent terminology for types of analysis. Of course, these revisions will improve reporting only if authors and journals adhere to them. These findings also highlight the need for all individual patient data to be made accessible to readers of the published article.