dat.hart1999 {metadat} | R Documentation |
Studies on the Effectiveness of Warfarin for Preventing Strokes
Description
Results from 6 clinical trials examining the effectiveness of adjusted-dose warfarin for preventing strokes in patients with atrial fibrillation.
Usage
dat.hart1999
Format
The data frame contains the following columns:
trial | numeric | trial number |
study | character | study name (abbreviated) |
year | numeric | publication year |
x1i | numeric | number of strokes in the warfarin group |
n1i | numeric | number of patients in the warfarin group |
t1i | numeric | total person-time (in years) in the warfarin group |
x2i | numeric | number of strokes in the placebo/control group |
n2i | numeric | number of patients in the placebo/control group |
t2i | numeric | total person-time (in years) in the placebo/control group |
compgrp | character | type of comparison group (placebo or control) |
prevtype | character | type of prevention (primary or secondary) |
trinr | character | target range for the international normalized ratio (INR) |
Details
The 6 studies provide data with respect to the number of strokes in the warfarin and the comparison (placebo or control) group. In addition, the number of patients and the total person-time (in years) is provided for the two groups. The goal of the meta-analysis was to examine the effectiveness of adjusted-dose warfarin for preventing strokes in patients with atrial fibrillation.
Concepts
medicine, cardiology, incidence rates
Author(s)
Wolfgang Viechtbauer, wvb@metafor-project.org, https://www.metafor-project.org
Source
Hart, R. G., Benavente, O., McBride, R., & Pearce, L. A. (1999). Antithrombotic therapy to prevent stroke in patients with atrial fibrillation: A meta-analysis. Annals of Internal Medicine, 131(7), 492–501. https://doi.org/10.7326/0003-4819-131-7-199910050-00003
Examples
### copy data into 'dat' and examine data
dat <- dat.hart1999
dat
## Not run:
### load metafor package
library(metafor)
### calculate log incidence rate ratios and corresponding sampling variances
dat <- escalc(measure="IRR", x1i=x1i, x2i=x2i, t1i=t1i, t2i=t2i, data=dat)
dat
### meta-analysis of log incidence rate ratios using a random-effects model
res <- rma(yi, vi, data=dat)
res
### average incidence rate ratio with 95% CI
predict(res, transf=exp)
### forest plot with extra annotations
par(mar=c(5,4,1,2))
forest(res, xlim=c(-11, 5), at=log(c(.05, .25, 1, 4)), atransf=exp,
slab=paste0(study, " (", year, ")"),
ilab=cbind(paste(x1i, "/", t1i, sep=" "),
paste(x2i, "/", t2i, sep=" ")),
ilab.xpos=c(-6.5,-4), cex=.85, header="Study (Year)")
op <- par(cex=.85, font=2)
text(c(-6.5,-4), 8.5, c("Warfarin", "Control"))
text(c(-6.5,-4), 7.5, c("Strokes / PT", "Strokes / PT"))
segments(x0=-8, y0=8, x1=-2.75, y1=8)
par(op)
### meta-analysis of incidence rate differences using a random-effects model
res <- rma(measure="IRD", x1i=x1i, x2i=x2i, t1i=t1i, t2i=t2i, data=dat)
res
## End(Not run)