I'm trying to run a generalised linear mixed effects (binomial-normal) meta-analysis for 7 randomised studies, where each study records the presence of an adverse event within the treatment and placebo populations (exposure and control).
To do this, I'm hoping to use the metabin function (meta package). However, I'm getting an error and I'm not sure why. E.g. running this code:
install.packages('meta')
# Data
data<-data.frame(exposure.events=c(11,34,152,4,60,3,25), exposure.population=c(184,152,9500,77,2012,15,60), control.events=c(3,33,4729,133,1441,1,25), control.population=c(184,375,613978,15865,480485,105,238), Study=c("1","2","3","4","5","6","7"))
# Calling metabin
metabin(event.e=exposure.events, n.e=exposure.population, event.c=control.events, n.c=control.population, studlab=Study, data=data, method="GLMM",model.glmm = "CM.AL",method.tau = "ML")
I get this output:
Error in metafor::rma.glmm(ai = event.e[!exclude], n1i = n.e[!exclude], : Cannot fit ML model.
I've also tried calling the rma.glmm function directly (instead of doing this via metabin), but get the same error message. I've also tried reading the source code for rma.glmm but I'm not sure I understand what's going on. However, I think the issue is related to the third study (the largest), and in particular the size of the control population, as both of the following run smoothly:
# Modifying 3rd row's control population
data<-data.frame(exposure.events=c(11,34,152,4,60,3,25), exposure.population=c(184,152,9500,77,2012,15,60), control.events=c(3,33,4729,133,1441,1,25), control.population=c(184,375,61378,15865,480485,105,238), Study=c("1","2","3","4","5","6","7"))
metabin(event.e=exposure.events, n.e=exposure.population, event.c=control.events, n.c=control.population, studlab=Study, data=data, method="GLMM",model.glmm = "CM.AL",method.tau = "ML")
# Deleting 3rd row
data<-data.frame(exposure.events=c(11,34,4,60,3,25), exposure.population=c(184,152,77,2012,15,60), control.events=c(3,33,133,1441,1,25), control.population=c(184,375,15865,480485,105,238), Study=c("1","2","3","4","5","6"))
metabin(event.e=exposure.events, n.e=exposure.population, event.c=control.events, n.c=control.population, studlab=Study, data=data, method="GLMM",model.glmm = "CM.AL",method.tau = "ML")
Is this a convergence problem, and does anyone know if there is any way around this? The only other thing I can find about this error message is for a problem (and thus solution) which does not apply to me.
Any help would be really appreciated :)