As I mentioned in the 'methodological quality' forum, I am currently working on a risk association meta-analysis involving case-control studies.

Not surprisingly, our meta-analysis has a substantial heterogeneity of I-squared of 90%. We are trying to do a metaregression and subgroup analysis which might explain some of the heterogeneity.

The question I have is how do we form a regression equation in the form of y = a+bx? Is Y here the 90% heterogeneity? And the regression variable (b1, b2, b3, etc) the covariates that I will be using for the metaregression?

Also, how does one do a metaregression in STATA? I am currently using comprehensive meta-analysis and it is working well, but I would like to learn to use the metareg command in STATA.

Thanks so much.