One of the main objectives of a meta-analysis is to obtain reliable estimates of treatment effects when RCT results are not sufficient. The optimal information size (OIS) can be defined as the minimum amount of information needed in a meta-analysis to obtain reliable conclusions about an intervention. The calculation of OIS suggests a limit on the conduct of clinical trials in the area, indicating whether the existing information is sufficiently convincing to the extent that new RCTs on that subject are no longer needed.
The OIS assumes that all RCTs studied are part of a single large RCT. However, when we observe data heterogeneity, it is not appropriate to make this kind of assumption. Consequently, heterogeneity should be considered when the OIS is calculated, since its increase requires a larger information size.
In this sense my questions are as follows:
- How to calculate the optimal information size (OIS) adjusted for meta-analysis heterogeneity?
- If there is no possibility of determining if the meta-analysis is conclusive using the tool of the calculation of the OIS, is it possible and advisable to perform a qualitative evaluation of the confidence interval generated by the meta-analysis?
The recent paper published in BMJ may help to answer your first question:
Article Impact of heterogeneity and effect size on the estimation of...
Thank you so much Kenneth Lo for your reply as well as for sharing the reference. I will check out! I really appreciate it.
Best Regards,
Luis
Dear Prof. Luís, according to Higgins and Green in the Cochrane Handbook (2011) you can deal with the heterogeneity, so please, take a look at the chapter 9.6 Investigating heterogeneity. About the Network Meta-analysis and the Optimum size of information adjusted for heterogeneity (OSI-H) can be calculated in conjunct with other parameters. So, you can read Georgia Salanti and Sofia Dias in many articles and also videos. There's a book by Sofia Dias - NMA for Decision Making, 2018. You can also see the following summary at the page: https://methods.cochrane.org/sites/methods.cochrane.org.statistics/files/public/uploads/SMG_training_course_cardiff/2010_SMG_training_cardiff_day1_session4_harbord.pdf. You can also find some formulas in a Brazilian Dissertation written by Mathias Azevedo Bastian Bressel about pharmacological interventions and he used the TOI/OIS: https://www.lume.ufrgs.br/bitstream/handle/10183/16365/000695956.pdf?sequence=1
So, I think with this material and the Kenneth Lo's material you will have a good overview about so many important points to reflect and think critically. Don't forget to read the Cochrane Handbook. If you need a special version, I can send you by email, Ok? Have a nice weed ahead! Best regards from Brazil. Ro
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