This isn't a simple question to answer. In CA agents are NOT allowed to tell you that you won't get coverage. It's up to the Insurance company underwriters.
Height and weight would also be a factor. What medications are being taken and their cost. It's not necessarily a question of what the Insurance Company thinks, but what does the medical field think?
When these types of questions come up - I look at the Insurance Company Underwriting Guide - BUT, it's confidential... What's really more meaningful is www.webmd.com and then you have an idea of what the disease is, how it progresses, what medications are available, etc.
The Insurance Companies aren't really interested in paying more for brand name Rx, then you are paying in premium.
For individuals who have been denied - there is always Mr. Mip. more info available at www.steveshorr.com/mr.mip.htm if you belong to an employer group - this question is meaningless - it's guaranteed issue.