how to calculate odd ratios with R?
Dear Luigi You could try the epitools package which gives a large number of ways of doing this. I would have thought that using Wald intervals for the log odds ration was not optimal with small frequencies. Michael
On 06/07/2020 14:01, Luigi Marongiu wrote:
Hello,
Is it possible to calculate with a single function the odd ratios?
Now I can use this implement:
```
or <- (De/He)/(Dn/Hn) # Disease exposed, Healthy non-exposed
logo <- log(or)
x <- sqrt(((1/De) + (1/He) + (1/Dn) + (1/Hn)))
lower_ci = exp(logo - 1.96*x)
upper_ci = exp(logo + 1.96*x)
cat("OR:", round(or, 3), "(", round(lower_ci, 3), "-", round(upper_ci, 3), ")",
spe = "")
```
for instance,
```
De <-6
Dn <-3
He <-4
Hn <-5
or <- (De/He)/(Dn/Hn)
logo <- log(or)
x <- sqrt(((1/De) + (1/He) + (1/Dn) + (1/Hn)))
lower_ci = exp(logo - 1.96*x)
upper_ci = exp(logo + 1.96*x)
cat("OR:", round(or, 3), "(", round(lower_ci, 3), "-", round(upper_ci, 3), ")",
spe = "")
OR: 2.5 ( 0.37 - 16.889 )
``` Is there a simple function from some package that can also add a p-value to this test? Or how can I calculate the p-value on my own?