What is the outcome of not treating cushings?

I draged my dog from vet to vet for a bad skin rash until finally one suggested to take her to a specialist. They took all kinds of tests and finally told me she may have cushings.I declined.That was at least 4 years ago. She has been doing fine. Two days ago she went to the vet for choclate poisening and it was recommended again. My dog has been fine for the last four years. Is someone out there who had the same experiance ? My dog is a cocker/dachs mix and is 16 yrs old.|||I had a dog with cushings - diagnosed at age 12, although she probably had the problem for many years. She was very fat and and always overheated. Anyhow, they put her on Lysodren (one pill each day) and after a few weeks she embarked on a second puppyhood - it was amazing. We put her on a diet and she reached a normal weight in a few months. She gained all sorts of energy and became more active. She lived to be almost 19 years old.