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dat.hart1999

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.

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, 492–501.

Examples

### copy data into 'dat'
dat <- dat.hart1999

### 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(dat$study, " (", dat$year, ")"),
       ilab=cbind(paste(dat$x1i, "/", dat$t1i, sep=" "),
       paste(dat$x2i, "/", dat$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

metafor

Meta-Analysis Package for R

v2.4-0
GPL (>= 2)
Authors
Wolfgang Viechtbauer [aut, cre] (<https://orcid.org/0000-0003-3463-4063>)
Initial release
2020-03-19

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