[R-meta] Mismatch between output from sub-group analysis and forest plot

[Joao Afonso]

Dear all,

Sorry for the double posting and previous "messy" message. I am
conducting a meta-analysis on prevalence and incidence data. As there
is plenty of heterogeneity I am doing a sub-group analysis. However I
am finding the output of the same and forest plots produced to have
different values for the pooled estimates. I am using the double
arcsine transformation and then have the data back-transformed to
produce the estimates. The model is the following:

iies.da.lcmbi<-ies.da %>%
  filter(is.na(lcmbi)==FALSE)

subganal.lcmbi=rma(yi, vi, data=ies.da.lcmbi, mods=~lcmbi, method="DL")
pes.da.lcm=rma(yi, vi, data=ies.da.lcmbi, mods=~lcmbi=="Records", method="DL")
pes.da.records=rma(yi, vi, data=ies.da.lcmbi, mods=~lcmbi=="Locomotion
Scoring Method", method="DL")
pes.subg.lcmbi=predict(subganal.lcmbi,
transf=transf.ipft.hm,
targ=list(ni=prevalence_2020_cow_nomv$ssizeanimal))
dat.samevar=data.frame(estimate=c((pes.da.lcm$b)[1], (pes.da.records$b)[1]),
stderror=c((pes.da.lcm$se)[1], (pes.da.records$se)[1]),
tau2=subganal.lcmbi$tau2)
pes.da.lcmbi=rma(estimate, sei=stderror,
method="DL",
data=dat.samevar)
pes.lcmbi=predict(pes.da.lcmbi, transf=transf.ipft.hm,
targ=list(ni=prevalence_2020_cow_nomv$ssizeanimal))
print(pes.da.lcm, digits=3)
print(pes.da.records, digits=3)
print(subganal.lcmbi, digits=3)
print(pes.lcmbi, digits=3)


And to produce the forest plot I use the following code:

subganal.lcmbi=rma(yi, vi, data=ies.da.lcmbi, mods=~lcmbi, method="DL")
pes.summary=metaprop(nlameanimal, ssizeanimal, author, data=ies.da.lcmbi,
                     sm="PFT",
                     method.tau="DL",
                     method.ci="NAsm",
                     byvar=lcmbi,
                     tau.common=TRUE,
                     tau.preset=sqrt(subganal.lcmbi$tau2))
precision=sqrt(ies.da.lcmbi$vi)
jpeg(file="forest_cow_cow_lcmbi.jpeg", width=11, height=12, units="in", res=300)
forest(pes.summary,
       xlim=c(0,1),
       pscale=1,
       rightcols=FALSE,
       leftcols=c("studlab", "effect", "ci"),
       leftlabs=c("Study", "Prevalence", "95% C.I."),
       text.random="Prevalence of Lameness in British Dairy Cattle",
       bylab = "Lameness Data Source",
       print.byvar = TRUE,
       xlab="Prevalence of Lameness", smlab="",
       weight.study="random", squaresize=0.5, col.square="navy",
       col.diamond="maroon", col.diamond.lines="maroon",
       pooled.totals=FALSE,
       comb.fixed=FALSE,
       fs.hetstat=10,
       print.tau2=TRUE,
       print.Q=TRUE,
       print.pval.Q=TRUE,
       print.I2=TRUE,
       digits=2,
       sortvar = precision)
dev.off()

What could I be doing wrong? I will be extremely grateful for any help
or guidance.

Wishing all a great afternoon,

Joao

-- 
João Afonso
DVM, MSc Veterinary Epidemiology
PhD Student
Department of Infection and Global Health
University of Liverpool
+351914812305