Ryan insisted that he felt "very good" about the bill's prospects but acknowledged that House leadership was "making fine-tuning improvements to the bill to reflect people's concerns."
A House vote was scheduled for Thursday.
"We believe we should have even more assistance. And that's one of the things we're looking at for that person in their 50s and 60s because they experience higher health care costs," the Wisconsin Republican said.
Under the GOP plan, older people who are not yet eligible for Medicare stand to be the biggest losers. It would shrink the tax credits they use to help buy insurance and it would increase their premiums because the bill allows insurers to charge more as people age and become more susceptible to health problems.
A Congressional Budget Office analysis last week said a 64-year-old with income of $26,500 would pay $1,700 out of pocket for insurance under the Affordable Care Act, compared with $14,600 under the GOP plan. It estimated that 24 million people of all ages would lose coverage over 10 years.
On Sunday, Ryan said he believed the CBO analysis was not accurate because Obamacare wouldn't be able to last 10 years. But he allowed the additional assistance was one of several House revisions to be discussed in advance of Thursday's vote, along with possible changes to help low-income people more with tax credits and require able-bodied Medicaid recipients to meet work requirements.
"We think that we should be offering even more assistance than what the bill currently does," he said.
Health and Human Services Secretary Tom Price also said legislative revisions were possible.
"If it needs more beefing up ... for folks who are low income, between 50 and 64 years of age, that's something that we've talked about, something that we've entertained, and that may happen throughout the process," he said.
Their comments came as President Donald Trump and House leaders seek to win support from GOP skeptics as prospects for the bill remain wobbly. Last week, Trump agreed to add fresh Medicaid curbs to appease some conservatives. But moderate Republicans are balking over the CBO's findings that millions more people would lack coverage even while premiums in many cases could rise.
In a Facebook post Saturday night, Rep. Brian Fitzpatrick, R-Pa., said he couldn't vote for the bill, stressing a need "to take our time and to get this right." He joins GOP Rep. John Katko, from a closely divided district in upstate New York, who cited inadequate insurance access and cost controls.
In the Senate, where Republicans hold a narrow 52-48 majority, prospects for the GOP bill also were uncertain as both moderates and conservatives criticized it.
Sen. Susan Collins, R-Maine, said she would not vote for the measure without additional changes to provide more aid to older Americans. She also wants an improved proposal that would cover more Americans and offer better Medicaid benefits than the current GOP plan. She joins at least four other GOP senators in opposing the bill after conservative Sen. Ted Cruz of Texas said Sunday he wouldn't vote for it as is. Sens. Dean Heller of Nevada, Mike Lee of Utah and Rand Paul of Kentucky are also opposed.
"I cannot vote for any bill that keeps premiums rising," Cruz said.
Separately, Ryan said he also expected the House to make changes to Trump's proposed budget, which calls for a boost to military spending but big-time cuts in domestic programs. Trump's plan, for instance, would cut $5.8 billion from the National Institutes of Health, an 18 percent drop for the $32 billion agency that funds much of the nation's research into what causes different diseases and what it will take to treat them.
Ryan said Congress was proud to have passed the Cures Act last year, which calls for additional NIH money for "breakthrough discoveries on cancer and other diseases," so he expects the proposed NIH cut to be revised.
"I would say, this is the very, very beginning of the budget process," he said. "We are encouraged that we're seeing an increase in defense because we think our military has been hollowed out. But I will say that NIH is something that's particularly popular in Congress. ... So, that is something that I think in Congress you'll see probably some changes."
Ryan spoke on "Fox News Sunday," Price appeared on ABC's "This Week," Collins was on NBC's "Meet the Press" and Cruz spoke on CBS' "Face the Nation."
Trump may move GOP health care bill to the right, dooming it in the Senate
The Trump administration, under pressure from conservative lawmakers, appears increasingly open to changing legislation repealing and replacing Obamacare in order to placate the right -- but that may guarantee at least this version of the bill is as good as dead in the Senate.
The political calculation is setting off a domino effect on Capitol Hill.
Just days to go before a Thursday vote on the House GOP bill, moderate Republicans have already expressed deep reservations about making drastic reforms to the current health care system. Making additional changes to satisfy conservatives is certain to strengthen opposition among centrist Republicans.
But moving the bill to the right dooms the proposal in the Senate, where the GOP has a razor-thin majority.
For now, the White House appears fixated on shepherding the bill repealing the Affordable Care Act through the House, with a vote on the seven-year anniversary of President Barack Obama signing the law. In its 11th hour negotiations, Trump and his top deputies have made compromises to appease the GOP's most conservative faction.
After meeting with members of the conservative Republican Study Committee this week, Trump announced that the lawmakers in the room who had previously been "no" votes were now on board, thanks to legislative changes that the White House and House GOP leaders had agreed to.
The negotiations continued over the weekend.
Several conservative lawmakers opposed to the House GOP health care bill -- Rep. Mark Meadows, chairman of the House Freedom Caucus, and Sens. Ted Cruz and Mike Lee -- met with senior White House aides on Saturday at Mar-a-Lago.
Trump himself did not participate in the meeting, a White House official said. But the President's senior most aides -- chief of staff Reince Priebus, chief strategist Steve Bannon and policy aide Andrew Bremberg -- were present, according to a senior Republican familiar with the meeting.
'Bannon is definitely our ally'
Cruz, Lee and Meadows made the case for going further with the American Health Care Act, the name of the bill introduced by House Speaker Paul Ryan and other senior Republicans, and backed by Trump. According to the Republican source, discussion included phasing out Medicaid expansion earlier and repealing Obamacare rules like essential health benefits and requiring insurers to allow 26-year-olds to stay on his or her parents' insurance -- one of the most popular provisions of the Affordable Care Act.
Notably, Bannon appeared receptive to the conservative contingent, while Priebus and Bremberg advocated for Ryan's approach.
"Bannon is definitely our ally in the White House," the Republican source said.
Health and Human Services Secretary Tom Price said on ABC about the negotiations in the House: "It's a fine needle that needs to be thread. There's no doubt about it."
It's not clear whether the White House will announce further concessions following the Saturday gathering in Florida. A Freedom Caucus source simply told CNN on Sunday that the negotiations are continuing "in good faith."
But giving more ground to conservatives risks a hemorrhaging of support from House Republican moderates, who are already uncomfortable with and have said they cannot support the legislation in its current form.
Particularly troubling to more centrist Republicans is the Congressional Budget Office's prediction last week that the House legislation would lead to some 24 million more people being uninsured by 2026 than under Obamacare, as well as the projection that premiums would spike for vulnerable demographic groups like older and low-income Americans.
DOA in the Senate?
A more conservative version of the bill that Ryan originally unveiled would most certainly be dead on arrival in the Senate.
Multiple Senate Republicans have publicly aired grave concerns about restructuring Medicaid. Under Obamacare, 31 states opted to expand the program for low-income adults and 16 of those states have Republican governors.
GOP Sen. Susan Collins of Maine, for example, said this week that she could not support the House bill in its current form, particularly because of its effects on the ability of low-income seniors to afford health insurance.
The White House, too, has admitted that the House bill would have trouble in the Senate. Trump administration officials acknowledged to Republican senators at a White House meeting earlier this week that "they don't have the (Senate) votes to pass this in current form."
In an interview on CBS' "Face the Nation" on Sunday, Cruz briefly discussed his Mar-a-Lago visit, saying the meeting with the President's team spanned three hours. He added that he had spoken multiple times with Trump and Vice President Mike Pence about the bill.
"I am spending night and day meeting with House members, meeting with senators, meetings with the administration," Cruz said.
Cruz and others have advocated publicly for a much more sweeping, conservative bill, but said he had not managed to sway Trump yet. He described Trump as willing to listen to everyone and that the bill was still in an ongoing negotiation process.
"I think that the President right now is listening to the arguments on all sides," Cruz said.