-- The Republican health care plan would reduce the federal deficit by $119 billion oven 10 years and leave 23 more Americans without health insurance, compared with current law, according to a new report from the nonpartisan Congressional Budget Office.
The bill, known as the American Health Care Act, passed the House with only one vote to spare earlier this month. The Senate is preparing to rewrite the measure before holding a vote.
Republicans dismissed some of the report's conclusions while touting the proposed savings.
"This CBO report again confirms that the American Health Care Act achieves our mission: lowering premiums and lowering the deficit. It is another positive step toward keeping our promise to repeal and replace Obamacare," House Speaker Paul Ryan of Wisconsin said in a statement.
An earlier analysis of the bill estimated that 24 million Americans would lose health insurance by 2026. The CBO's updated assessment revised that figure but still found that 14 million fewer Americans would have insurance by 2018, compared with under Obamacare.
Senate budget rules require the AHCA to save $2 billion over 10 years in order to be taken up under reconciliation — a process that would allow Senate Republicans to pass the bill with only 51 votes.
Wednesday's report estimated that the GOP bill would raise premiums over time for people who are less healthy in states that seek and receive waivers from some critical Obamacare regulations.
The analysis undermines the Republican argument that the AHCA wouldn't negatively affect Americans with existing conditions. The CBO report said that the bill would by making health care less affordable for some people in states that obtain the waivers.
"Community-rated premiums would rise over time, and people who are less healthy (including those with pre-existing or newly acquired medical conditions) would ultimately be unable to purchase comprehensive nongroup health insurance at premiums comparable to those under current law, if they could purchase it at all," the report read.
The report echoes earlier analyses that predicted that premiums could rise significantly for a portion of the population that would receive tax credits less generous than under the current law — namely, older and poorer policy holders.
The CBO's analysis of subsidies in 2026 indicates that under the GOP bill, net premiums for a 64-year-old earning $28,500 a year would rise from $1,700 currently to $13,600 to $16,100, depending on whether the person lives in a waiver state.
Savings would be more common for wealthier individuals, who would benefit from tax credits pegged to age rather than income, according to examples cited by the CBO. Under the bill, an individual earning $68,200 annually would receive the same credit as someone the same age earning $28,500, according to the CBO.
Republicans on Capitol Hill and in the White House have criticized the CBO for inaccuracies in its analysis of the impact of the Affordable Care Act in 2010. While the CBO overestimated the number of people who would obtain insurance, it was correct in predicting that the number of uninsured would fall.
"History has proven the CBO to be totally incapable of accurately predicting how health care legislation will impact health insurance coverage," a White House official said Wednesday.
Even before the report was released, Republicans said the Senate is likely to make significant changes to the House proposal scored by the CBO.
"It's a technical, procedural step," said Senate Majority Leader Mitch McConnell of Kentucky. "Beyond likely reiterating things we already know — like that fewer people will buy a product they don't want when the government stops forcing them to — the updated report will allow the Senate procedural to move forward to work and draft its own health care legislation."
"We don't have the same bill that the House does. We're doing something different, so there are limits to its effectiveness, but it certainly informs our discussion," Sen. Jeff Flake, R-Ariz., said of the CBO report.
As with all CBO reports, Wednesday's analysis said that there are a number of factors that contribute to the uncertainty of its prognostications but that it "endeavored to develop estimates that are in the middle of the distribution of potential outcomes."
ABC News' Ali Rogin contributed to this report.