First of all, medicine is as much art as science. Very little of what a practicing physician does is affected one way or the other by the theory of evolution. Surgeons, for instance, learn their specialty by doing surgery, not by studying evolutionary biology.
Second, I am not convinced that a belief in Intelligent Design is necessarily a rejection of science. (Young-earth creationism is another matter—it is both bad science and bad theology.) Neither evolution nor ID are relevant to the physical sciences: a person could accept ID and still do excellent work in astronomy, chemistry, physics, or geology. Even in some biological fields, evolution is not a big issue.
> Very little of what a practicing physician does is affected one way or the other by the theory of evolution.
But a rejection of science leads to bad doctoring. I would be as leery of a surgeon who believed that the moon was made of green cheese as of one who rejected 150 years of biology, chemistry, physics and geology.