[R] logistic regression

Kim Mouridsen
Sun, 07 Dec 2003 17:45:38 -0000

Dear R-experts

A binary response is observed for patients receiving one of three different
drugs injected in different doses. That is for each drug (treatment) we have a
dose-response model. Additionlly the patient's age and gender is recorded.

Initially I ran three logistic regressions, one for each drug type with gender
as categorical variable and age and dose as continuous variables. If I want to
know the effect of, say, gender on the response I now have three odds ratios -
one for each dose response model.

My question is: How can I compare the three odds ratios? Is it possible in R
to combine the three dose-response models into a single model to get an
overall estimate of the effect of age?
Can I do something like
lr <- glm(vom ~ therapy*age + therapy*gender +
therapy*cisdose+therapy*cardose+therapy*cycdose,family=binomial,data=emrisk)

Thanks in advance!
Kim Mouridsen.

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