I would like to know if I suspect that two studies (same authors) was based on the same patients but with different follow-up. Can we include both? Can we dowgrade one of them (high risk of bias) to exclude one in a sensitivity analysis? I cannot find any clear answer in the different tools assessing quality of evidence (GRADE, RoBs, ...)
The usual thing in these cases is if there is a cohort of patients that have been published at two different times, to avoid bias, only one of the two will be used in the meta-analysis. Generally the one that has a longer follow-up period.
1. Contact the authors with question to verify duplicate publication.
2. Include one of two: a) the most informative one on risk of bias; b) the one with most transparent reporting of outcome data (not necessarily the one with longest follow up period).
Dear Marie,
It is an issue that I have come across a few times. If it is the same study with different time-points of assessment and you are interested in both of them, the common approach is to include the two papers as a single study. If a clinical registration number is reported in both papers and they are the same, it is a strong indication that it is the same study. If it is the same study, the authors should acknowledge this in the latest publication. I agree that it is a good idea to contact the authors for a confirmation. Consider providing the study with a high risk of reporting bias.
This phenomenon is called duplicate publication of different outcome sets.
Additionally, conducting a leave-one-out sensitivity analysis by excluding one of these studies will help determine whether its inclusion significantly affects the overall pooled estimates.
- Badges
- Science topic