r - Calculate exact proportion using metaprop (meta package in R)

Question

I am doing a meta-analysis on patients who are intubated when they are given a particular drug. Specifically, I have 17 studies. In each of those studies, some fraction of the patients get intubated. Different subgroups have different intubation risk.

My problem is that when I do a forest plot, the proportions do not seem correct.

library(meta)
studies <- c("Cong 2015", "Gangathimmaiah 2017", "Parsch 2017", "Hopper 2015", 
              "Isbister 2016", "Kowalski", "Riddell 2017", "Burnett 2012",
              "Burnett 2015", "Cole 2016", "Cole 2017", "Hollis 2017", "Iwanicki 2014", 
              "Keseg 2014", "Olives 2016", "Scaggs 2016", "Schepke 2015")
obs <- c(0, 3, 0, 0, 0, 0, 2, 2, 14, 25, 28, 10, 16, 8, 85, 0, 2)
denom <- c(18, 21, 22, 32, 49, 5, 23, 12, 49, 64, 49, 38, 32, 35, 135, 7, 52)
setting <- c("AMT", "AMT", "AMT", "ED", "ED", "ED", "ED", "EMS", "EMS", 
             "EMS", "EMS", "EMS", "EMS", "EMS", "EMS", "EMS", "EMS")
m1 <- metaprop(obs, denom, studies, comb.random=FALSE, byvar=setting, 
               bylab="Setting", byseparator=": ")
forest(m1, print.tau2 = FALSE, col.by="black", text.fixed = "Total",
       text.fixed.w = "Subtotal", rightcols = c("effect","ci"), 
       leftlabs=c("Study","Intubated","Total"))

When I do this plot, the first subgroup shows 3 of 61 patients intubated. However, the proportion is shown as 0.09, but it should be 0.05.

What am I doing wrong?

Answer 1

您应该使用以下method="GLMM"参数metaprop：

library(meta)
library(metafor)

m1 <- metaprop(obs, denom, studies, comb.random=F, byvar=setting, 
               bylab="Setting", byseparator=": ")
m2 <- metaprop(obs, denom, studies, comb.random=F, byvar=setting, 
               bylab="Setting", byseparator=": ", method="GLMM")
m2$w.fixed <- m1$w.fixed

forest(m2, print.tau2 = FALSE, col.by="black", text.fixed = "Total",
       text.fixed.w = "Subtotal", rightcols = c("effect","ci"), 
       leftlabs=c("Study","Intubated","Total"))