• Monthly adjustments kick in next year for individuals with modified adjusted gross income above $91,000.
• For married couples filing a joint tax return, that threshold is $182,000. 
• Medicare enrollees with higher income have paid more for Part B since 2007 and for Part D since 2011.

Medicare beneficiaries who pay monthly surcharges for premiums may want to take note of how much more they'll be charged next year.

With the standard monthly premium for Part B (outpatient care coverage) now set at $170.10 for 2022, the so-called income-related monthly adjustment amounts, or IRMAAs, will result in higher-income beneficiaries paying anywhere from $238.10 to $578.30 each month for that coverage. About 7% of Medicare's 63.3 million beneficiaries with Part B will pay IRMAAs next year, according to the Centers for Medicare & Medicaid Services.

The adjustments kick in next year for individuals with modified adjusted gross income — this is your adjusted gross income plus tax-exempt interest — above $91,000. For married couples filing a joint tax return, that amount is $182,000. 

For Part D prescription drug coverage, the additional monthly amounts range from $12.40 to $77.90 with the same income thresholds applied. (See chart below.)

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Those amounts are in addition to any premium you pay for Part D, whether through a standalone plan or via a Medicare Advantage Plan, which typically includes drug coverage.

About 8% (3.9 million) of Medicare's 48.5 million beneficiaries with Part D will end up paying the surcharges, according to the Centers for Medicare & Medicaid Services.

Higher-income beneficiaries have paid more for Part B since 2007 and for Part D since 2011. (Part A has no premium has long as you have a 10-year work history of paying into the system through payroll taxes.)

Generally speaking, your tax return from two years earlier is used to determine whether you are subject to the surcharges, because it usually is the most recent filing available. So for 2022, it would be your 2020 return (which was due this year).

If your income has dropped and is not reflected in a tax return yet, you can ask the Social Security Administration to reconsider.

Events that qualify as justification for reducing or eliminating the IRMAAs include marriage, death of a spouse, divorce, loss of pension or the fact that you stopped working or reduced your hours.

You'll need to fill out a form and provide supporting documents to justify your appeal. Suitable proof may include a letter from your former employer (if you're no longer working) or something similar that shows evidence of reduced income.