I am conducting a Meta-Analysis of a clinical intervention in randomised trials. I am using the RevMan Software of the Cochrane Foundation. The problem regards the extraction process of relevant outcome results that are typically needed for Meta-Analysis.
- I have one primary outcome, which is "symptom level of disease X" but different scales to measure symptom level of "disease X". Lets say "Scale A, Scale B, Scale C".
- The different study papers report the outcomes in different ways
- one study only gives as result a "mean change score" with a Confidence Interval 95%, but the program requires a "Mean" as well as "Standard Deviations" (SD) for the "Intervention" as well as for the "Control". Is it possible to get the Mean and the SD from the single given "change score"? (The baseline values for each group are given.)
- another study only gives the results in a comparison of "percentage of people having a cut point of XYZ"
- while other studies give the Mean Difference and Standard Deviations of different outcome scales
- The "properties" of the analysis in Review-Manager are as follows:
- "Continuous Data Type" (since the scales have different measurements/pointage system from 1-20 or 1-10)
- Statistical Method: "Inverse Variance" (As far as I understand this is useful for different data type entry possibilities)
- Analysis Model "Random Effects" (It seems to offset the heterogeneity)
- Effect Measure: "Mean Difference"
Will it be sensible to conduct the Meta-Analysis in this way?
I already tried finding answers in the Cochrane Handbook, RevMan Tutorials, as well as a lot of articles and parts of books about meta-analysis.