The paper discussed the use of drug X in condition Y, submitted to journal A. It is a double blind randomised controlled trial, presenting the 1 year result in 129 women. It finds that drug X helps in condition Y. The authors published a similar paper in journal B, 2 months before submission of this paper to journal A. The journal B paper studied the same question in 601 women with a 2 year follow-up. The only new feature in the journal A paper is that all the women have a level of index greater than 1 standard deviation below the mean. The journal B study included those between -2.2 and +2.0 standard deviations. There was therefore some overlap of the inclusion criteria in the two trials. The journal A paper does not make explicitly clear whether the women described form part of a subgroup of the cohort discussed in journal B. In fact, they make only passing reference to that paper, but do not discuss its relation to the paper they are submitting to journal A. The authors did not supply a copy of the journal B paper when submitting the journal A paper. What should we do now?
The two sets of data overlap and the authors have not been explicit about this. The editor was advised to go back to the authors for an explanation and seek independent assessment of the degree of overlap.