metafor (version 1.9-9)

dat.normand1999: Studies on the Length of Hospital Stay of Stroke Patients

Description

Results from 9 studies on the length of the hospital stay of stroke patients under specialized care and under conventional/routine (non-specialist) care.

Usage

dat.normand1999

Format

The data frame contains the following columns:

study	numeric
study number	source
character	source of data
n1i	numeric
number of patients under specialized care	m1i
numeric	mean length of stay (in days) under specialized care
sd1i	numeric
standard deviation of the length of stay under specialized care	n2i
numeric	number of patients under routine care
m2i	numeric
mean length of stay (in days) under routine care	study

Source

Normand, S. T. (1999). Meta-analysis: Formulating, evaluating, combining, and reporting. Statistics in Medicine, 18, 321--359.

Details

The 9 studies provide data in terms of the mean length of the hospital stay (in days) of stroke patients under specialized care and under conventional/routine (non-specialist) care. The goal of the meta-analysis was to examine the hypothesis whether specialist stroke unit care will result in a shorter length of hospitalization compared to routine management.

Examples

### load data
dat <- get(data(dat.normand1999))

### calculate mean differences and corresponding sampling variances
dat <- escalc(measure="MD", m1i=m1i, sd1i=sd1i, n1i=n1i, m2i=m2i, sd2i=sd2i, n2i=n2i, data=dat)
dat

### meta-analysis of mean differences using a random-effects model
res <- rma(yi, vi, data=dat)
res

### meta-analysis of standardized mean differences using a random-effects model
res <- rma(measure="SMD", m1i=m1i, sd1i=sd1i, n1i=n1i, m2i=m2i, sd2i=sd2i, n2i=n2i, 
           data=dat, slab=source)
res

### draw forest plot
forest(res, xlim=c(-7,5), alim=c(-3,1), cex=.8)
text(-7, 11, "Study/Source",          pos=4, cex=.8)
text( 5, 11, "Observed SMD [95% CI]", pos=2, cex=.8)