Proposals by Congressional Republicans to repeal the Affordable Care Act could cost the District government billions of dollars over the next decade, according to a report released Wednesday by D.C. Auditor Kathleen Patterson.

The report paints a bleak picture for District officials as they prepare to weather GOP efforts to repeal and replace former President Barack Obama’s signature health-care law as well as revamp Medicaid, the federal government’s health-insurance program for the poor.

It came one day after Rep. Tom Price (R-Ga.), Trump’s nominee to head the Department of Health and Human Services, endured a grilling during his Senate confirmation hearing by Democrats who expressed concerns similar to those raised in Patterson’s report.

The changes to the health-care market under consideration on Capitol Hill could result in more than 100,000 D.C. residents losing their insurance unless the District’s government steps in to offer backup coverage, the auditor’s office found.

But such a rescue effort would not be cheap. The auditor’s report says a rollback of Obama’s expansion of Medicaid under the ACA would result in the District losing $563 million in federal funding in fiscal 2018 alone. That figure would grow steadily over time, reaching more than $1.1 billion in lost federal dollars a decade from now.

On top of that, Republican prescriptions for restructuring Medicaid could result in billions more in lost federal revenue, Patterson estimated.

Two ideas popular among GOP legislators on Capitol Hill — the conversion of Medicaid into block grants to the states or fixed, per-capita allotments of cash — would cost $2.1 billion or $1.9 billion by the 2028 fiscal year, respectively.

“Given the magnitude of these possible losses, it is clear that the District could not readily supplement the lost federal funding to maintain the level of coverage for residents who currently benefit from the ACA and the Medicaid expansion program,” Patterson noted in the report, which was prepared at the request of Council member Jack Evans (D-Ward 2).

The report was based on data from D.C.’s Department of Health Care Finance, as well as analysis of health-care plans put forward by Republicans in Congress.

Earlier this month, Mayor Muriel E. Bowser wrote a letter to House Majority Leader Kevin McCarthy (R-Calif.) opposing efforts to repeal and replace Obamacare.

“The repeal of all or part of the Affordable Care Act would disrupt our insurance market, impair insurers, and increase costs to the district and consumers,” Bowser wrote.

The District is particularly vulnerable to tampering with federal health programs because of its residents’ abnormally heavy reliance on Medicaid.

During the 2016 fiscal year D.C. had a monthly average of 261,768 people covered under Medicaid — nearly 40 percent of the population. Of those, 75,828 gained coverage through the ACA Medicaid expansion.

By contrast, effects on the District from changes to the insurance exchanges established under the ACA — clearinghouses where people without health insurance can shop for plans and determine their eligibility for federal subsidies — would not be as severe.

A relatively small number of D.C. residents using the exchanges qualify for the subsidies, receiving about $2.8 million in total assistance last year, according to the audit.