[R] prevalence in logistic regression lrm()

[array chip]

Hi, I am wondering if there is a way to specify the prevalence of events in logistic regression using lrm() from Design package? Linear Discriminant Analysis using lda() from MASS library has an argument "prior=" that we can use to specify the prevalent of events when the actual dataset being analyzed does not have a representative prevalence. How can we incorporate this information in lrm()? The concern I have is if my dataset does not have a representative prevalence, then the probability generated by lrm() will not be meaningful. Thanks

John