In 2016, higher earners  (>$85k single/ $170k couples) could see a significant increase to their Medicare Part B (doctor visits) premium. Additionally, Social Security’s ‘Hold Harmless’ provision tying the Medicare premium increase to cost of living adjustment (COLA) applies to only those Medicare subscribers who are already taking Social Security benefits. It does not apply to those who have deferred  their Social Security benefits (file/suspended).

Read more on this issue in this article from Anne Tergesen http://finance.yahoo.com/news/unexpected-spike-medicare-premiums-151800550.html