Those unlucky patients may go from paying $104.90 per month to $159.30 because of a simple “hold harmless” provision that says premiums can’t go up for Social Security recipients if there’s not cost-of-living adjustment for the given year. That means the 7 million Medicare Part B enrollees that aren’t receiving Social Security will shoulder the burden of premium rises.

The 70% of Medicare Part B users that won’t see a premium increase next year are those people currently receiving Social Security benefits. The premium increase burden will fall, instead, on people who either will enroll in Part B for the first time in 2016, don’t currently collect Social Security, or who are billed directly for their Part B premium.

As Mark Lumia, founder of True Wealth Group, put it in an interview with USA Today: “Under current law, Part B premiums for other beneficiaries must be raised enough to offset premiums foregone due to the hold harmless provision.”