employers get no access to your medical records. none.
insurers will ask, but you do not need to give permission.
but yes, many jobs would require background checks.this would NOT include access to your medical records, though it well might include a thorough questionnaire for you doc to attest to certain criteria.
i told my doc a few months after i quit, and that's been hugely beneficial. it helped me to have been up front when i needed to go for surgery and was worried about the morphine.
it helped me when i was going through a bad spell and couldn't see how depressed i was, yet she saw it and talked with me about an increased danger of relapse .
that kind of stuff.
it ended up helping her to help me better.