Data integrity of the 223 randomized controlled clinical trials produced by multiple groups centered around a single author

Background

We suspected unusual consistency in baseline variables and dropout rate in the randomized controlled trials (RCTs) produced by a team of researchers. We define this group of RCTs by the presence of an individual researcher in the author team, whom we call here the ‘key author’. We investigated the trustworthiness of these data and with that its scientific and clinical value.

Methods

Systematic searches were performed in Embase, PubMed, and Web of Science for all the RCTs published by this author team. The final search date was 01/08/2024. Preregistered analyses tested for the presence of sampling variability in baseline characteristics of the RCTs and participant flow, operationalized as an even vs. odd dropout and an equal dropout, through the trials. Control data was gathered from RCTs that were performed by other groups but on similar topics as the investigated RCTs.

Results

We found strong evidence that the expected sampling variability was not present in the 223 RCTs produced by this group relative to the expected uniform distribution (Bayes Factor [BF₁₀] > 100000) and to what we observed in the 103 control RCTs (BF₁₀ = 172). The proportion of even vs. odd dropout (e.g., 4 vs. 3) was .76 (95% CI = 0.70, 0.81) and different from the theoretical value of .50 (BF₁₀ = 8.5×10¹¹) and from what we observed in control RCTs (BF₁₀ = 379). Equal dropout over arms of a trial was 3 to 4 times more likely in the tested trials than in the control trials, relative to what we observed in control trials (BF₁₀ = 1.8×10¹⁶). The results were not explained by the method of randomization or sample size. Associations were mostly evident when the ‘key author’ had first or last authorship.

Conclusion

It is unlikely that the RCTs by this team were generated through the process of randomization, and the flow of participants in these trials seems implausible. Hence, we question the scientific and clinical value of the RCTs that are produced by this team.

Registration

https://doi.org/10.17605/OSF.IO/8MTG6