Estimating the incidence of covid-19 in placebo arms of RCTs
library(meta); library(metafor)
## Warning: package 'meta' was built under R version 4.0.2
## Loading 'meta' package (version 4.19-0).
## Type 'help(meta)' for a brief overview.
## Warning: package 'metafor' was built under R version 4.0.2
## Loading required package: Matrix
## Warning: package 'Matrix' was built under R version 4.0.2
## Loading 'metafor' package (version 2.4-0). For an overview
## and introduction to the package please type: help(metafor).
study = c("Pfizer", "AZ", "Moderna", "J&J", "Sputnik", "Sinopharm")
nn = c(17511, 5829, 14073, 19544, 4902, 12737)
covid = c(162, 101, 185, 348, 62, 95)
inc = covid/nn
df = data.frame(study, nn, covid, inc)
m1 = metaprop(covid, nn, method="Inverse", studlab=study)
m1
## proportion 95%-CI %W(fixed) %W(random)
## Pfizer 0.0093 [0.0079; 0.0108] 17.1 17.0
## AZ 0.0173 [0.0141; 0.0210] 10.6 16.5
## Moderna 0.0131 [0.0113; 0.0152] 19.4 17.1
## J&J 0.0178 [0.0160; 0.0198] 36.4 17.4
## Sputnik 0.0126 [0.0097; 0.0162] 6.5 15.7
## Sinopharm 0.0075 [0.0060; 0.0091] 10.0 16.4
##
## Number of studies combined: k = 6
## Number of observations: o = 74596
## Number of events: e = 953
##
## proportion 95%-CI
## Fixed effect model 0.0134 [0.0126; 0.0143]
## Random effects model 0.0124 [0.0093; 0.0164]
##
## Quantifying heterogeneity:
## tau^2 = 0.1182 [0.0397; 0.7523]; tau = 0.3438 [0.1993; 0.8674]
## I^2 = 94.5% [90.6%; 96.8%]; H = 4.27 [3.26; 5.60]
##
## Test of heterogeneity:
## Q d.f. p-value
## 91.10 5 < 0.0001
##
## Details on meta-analytical method:
## - Inverse variance method
## - DerSimonian-Laird estimator for tau^2
## - Jackson method for confidence interval of tau^2 and tau
## - Logit transformation
## - Clopper-Pearson confidence interval for individual studies
forest.meta(m1, layout="RevMan5")
funnel.meta(m1)
