Distributions of baseline categorical variables were different from the expected distributions in randomized trials with integrity concerns

• Published in: Journal of clinical epidemiology Vol. 154; pp. 117 - 124
• Main Authors: Bolland, Mark J., Gamble, Greg D., Avenell, Alison, Cooper, David J., Grey, Andrew
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.02.2023; Elsevier Limited
• Subjects: Binomial distribution; Categorical variables; Chi-square test; Clinical trials; Continuity (mathematics); Data integrity; Datasets; Epidemiology; Expected values; Fabricated data; Humans; Integrity; Internal Medicine; Males; Mathematical analysis; P-values; Probability; Professional misconduct; Randomization; Randomized Controlled Trials as Topic; Research integrity; Statistical methods; Statistics as Topic; Systematic review; Variables; Fabricated data; Randomization; P-values; Data integrity; Statistical methods; Research integrity; Categorical variables; Data Integrity; Fabricated Data; Research Integrity; Statistical Methods
• ISSN: 0895-4356; 1878-5921; 1878-5921
• DOI: 10.1016/j.jclinepi.2022.12.018

Comparing observed and expected distributions of baseline continuous variables in randomized controlled trials (RCTs) can be used to assess publication integrity. We explored whether baseline categorical variables could also be used. The observed and expected (binomial) distribution of all baseline categorical variables were compared in four sets of RCTs: two controls, and two with publication integrity concerns. We also compared baseline calculated and reported P-values. The observed and expected distributions of baseline categorical variables were similar in the control datasets, both for frequency counts (and percentages) and for between-group differences in frequency counts. However, in both sets of RCTs with publication integrity concerns, about twice as many variables as expected had between-group differences in frequency counts of one or 2, and far fewer variables than expected had between-group differences of >4 (P < 0.001 for both datasets). Furthermore, about one in six reported P-values for baseline categorial variables differed by > 0.1 from the calculated P-value in trials with publication integrity concerns. Comparing the observed and expected distributions and reported and calculated P-values of baseline categorical variables may help in the assessment of publication integrity of a body of RCTs.