Humana is in the process of severing ties with St. Luke's in this area. If you keep your Humana Medicare Advantage Plan be advised if you go to St. Luke's you will be on the hook for out of plan costs. The mutual separation is over reimbursements to St. Luke's by Humana for Medicare Advantage payments. You know... the charges sent to Humana generally get settled for a much lower price than "retail" prices charged by hospitals.
United Health (under the banner of AARP), is dropping thousands of doctors in 10 States according to a Wall Street Journal article in today's edition. Again it is probably over reimbursements paid v. what the docs submit for their services.
If you have anyone you know oblivious to these changes in Medicare you might want to give them a heads up. Out of plan fees and costs can be a real shock to the wallet.