I am conducting a systematic review that includes 50 randomized trials en pre-post intervention analyses, reporting on about 38 different interventions and the same outcome measure. I am considering to use the GRADE approach to assess the certainty of evidence. However, this means I would have to do this separately for each of the 38 interventions. Most interventions are only assessed by one single study. So that means 38 times applying the GRADE approach, mainly on one and sometimes two studies reporting on the same intervention and the same outcome.

I am wondering whether it would add to our study to perform the GRADE approach for each intervention and also when there is just one study to assess, as heterogeneity for instance will be absent in that case.

I hope you can help! Thank you very much in advance.