metafor (version 1.9-2)

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: lll{ 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 sd2i numeric standard deviation of the length of stay under routine care }

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
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.normand1999)
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))
text(-7, 11, "Study/Source",          pos=4)
text( 5, 11, "Observed SMD [95% CI]", pos=2)