Im doing a meta-analysis of randomized interventional trials to compare between two types of surgeries.
The follow up period at which outcomes were reported varied between 6 weeks to 24 months. Some studies reported their results at different follow up points, whereas others reported results at one follow up point.
I want to ask about the most appropriate way to pool the studies together in this situation. Should I pool the data of the longest follow up available or should I rather subgroup the studies each study data according to the follow up point and report the pooled effect of each subgroup?
I performed both analyses. However, they were not matching. The first analysis revealed a significant difference between the two arms, while the second showed no significant difference in all subgroups.
The I2 of both analyses was 0%.