Medicare has long offered tax deductions for medical treatment and other medical expenses.
But in recent years, the tax breaks have gone beyond what Medicare is currently paying.
In the first quarter of 2018, the deduction was worth about $1.3 trillion, according to an analysis by Tax Analysts.
The total value of the deduction rose to $1 trillion in the second quarter of that year, the analysis found.
Tax Analyts also noted that medical expenses were up slightly last year.
The deduction has risen by more than $1 billion since 2015, the study found.
A spokesman for the House Ways and Means Committee said in an email that the committee is reviewing the tax credits to ensure they are working as intended.
The Medicare deduction is currently worth about a quarter of the total value paid by Medicare beneficiaries, and is worth about one-third of the cost of prescription drugs, according the Tax Policy Center.
The House Budget Committee recently proposed a compromise to limit the deduction, which would not affect taxpayers who are covered by private insurance plans.
The proposal would limit the amount that Medicare would pay out to doctors and hospitals to about $300 per day, or less than the cost to a single taxpayer.
But that would only apply to a limited number of services, such as physical therapy.
The committee said it plans to vote on the measure at a hearing on Friday.
The Senate Finance Committee is expected to vote Wednesday on a resolution urging the House to consider a plan that would cap the deduction at $400 per day.
That measure would apply to only about 1.5 percent of Medicare beneficiaries.