Im currently working on a meta-analysis of randomized controlled trials (RCTs).
These RCTs have reported their outcomes at different time points.
The maximum follow-up points were as follows: 1 months, 3 months, 6 months, and 48 months.
To pool the studies without double counting, I have decided to include the outcome data of the longest follow-up period of each study only.
My problem is: one of the studies maximum follow-up period was 48 months, which is considered an outlier in this case. This study also reports outcomes at 6, 12, and 24 months.
My first question:
Can I include the data of the shortest follow up-period data of this study instead, which is 6 months? My intention is to only make the data homogenous.
My second question:
I decided to do subgrouping for the studies based on intervention techniques to test for subgroup differences. Is it okay if one subgroup contained a single study? (no study was double-counted)