Before I moved to the Phils in 2013 I visited my local SS office. Talking to a woman that she varified that Medicare does not cover anyone in the Phils. I then asked why I should pay for it. She said I don't and that before I leave to come in and fill out a form and I could add that premium to my income.
So that's what I did and she assured me I would not be fined as a citizen with foreign residence. Now, I also checked and due to my standing I do not need to go through the whole "enrollement" process that a normal American residing in the 50 states would need to. I can enroll at any time. It may take a month or so to get it set and going again, but I wouldn't have to wait till January and all that to reactivate my Medicare.
Not sure what insurance you are receiving and all, but it seems to me the same rules would apply to you. There may be some other hurdles or paperwork to fill out depending on what insurance setup you are now under. Best of luck.