But millions of Americans will pay more for an insurance policy that comes with a much steeper deductible under the new Senate plan, according to some health economists and insurance experts. It could also make it much harder to find a comprehensive plan covering various conditions ranging from heart disease to depression that would not be prohibitively expensive.
“This is going to be a very unstable market” where only the very sickest people resort to buying coverage on the federal exchanges at much higher prices, said Paul B. Ginsburg, a health economist and the director of the Center for Health Policy at the Brookings Institution.
Those likely to suffer the most under the Senate plan are people who would not be eligible for any remaining subsidies, he said, because they could be priced out of the market. Most worrisome to those opposing the Senate bill is that states could give insurers leeway to offer skimpy plans that cover a lot less and exclude people with certain illnesses.
Insurers have been largely quiet since the Senate Republicans released their version of the bill on Thursday morning. But some did criticize the legislation for not doing more to help people pay for insurance.
“The draft bill does not expand coverage; it does not do enough to protect people in need of care; nor does it provide enough assistance to those who need help in paying for health care and coverage,” said Bernard J. Tyson, the chief executive of Kaiser Permanente, a California insurer that offers plans on the exchanges in eight states and in Washington.
If the Senate version becomes law, insurers could increase premiums for individual coverage by at least 20 percent more than the double-digit increases already under consideration. By 2020, other changes are likely to result in plans with much higher deductibles. People now getting tax credits that allow them to purchase a policy with a deductible of $3,500 would get subsidies for a plan where the deductible would nearly double, without any funding to pay their out-of-pocket costs.
Many people will face a Hobson’s choice, said Craig Garthwaite, a health economist at Northwestern’s Kellogg School of Management. They will have to choose between a plan with a premium they cannot afford or a plan with a deductible they cannot afford.
While lower premiums touted by Republicans could attract healthier people to buy coverage on the exchanges, other changes could still drive up prices, said Mr. Garthwaite, who is a registered Republican. “It could turn out to be higher premiums and higher deductibles,” he said.
One stark difference between the Senate bill and the Affordable Care Act is the decision to drop the mandate requiring insurance. That could inadvertently discourage the youngest and healthiest people from buying insurance, leaving a higher percentage of sicker people with expensive treatments on the exchanges, driving up insurers’ costs.
When Congress debated the Affordable Care Act under President Barack Obama, a major objective was to tackle soaring premiums and steep deductibles that Americans faced in their employer-based plans and when they bought coverage on their own.
On Thursday, Health Secretary Tom Price argued that Republicans needed to pass a replacement for the same reasons. “We’ve got prices going up, we’ve got deductibles going up, premiums going up,” he said in a television interview on Thursday. “We’ve got people that have an insurance card but they don’t have any care because they can’t afford the deductible.”
Some Republican policy experts are not convinced that this bill’s provisions would solve those problems. “Republicans are taking it and going in the opposite direction,” said Rodney L. Whitlock, a former aide to Senator Charles E. Grassley, Republican of Iowa. Mr. Whitlock thinks the bill’s changes in 2020 to allow insurers to offer plans with less generous coverage could lead to policies with “almost assuredly five digit” deductibles — $10,000 or more.
Insurers are assuaged that the bill provides temporary funding for the so-called cost-sharing reductions, federal money they receive to sell plans that cover out-of-pocket costs for people earning low incomes.
But those subsidies end after 2019, meaning that when people buy plans with much higher deductibles, they would be exposed to paying thousands of dollars in medical bills. It is difficult to see how someone making $40,000 a year will pay for health insurance that forces them to come up with $10,000, Mr. Whitlock said, meaning only the very sickest may be willing to try to pay for a plan to offset some medical expenses. “This is where Republicans are in a direction they are going to regret,” he said.
There are provisions aimed at reducing premiums, including federal funding to states to stabilize the market. High-deductible plans tend to carry lower premiums. Younger individuals would also pay much lower prices under the proposed bill; people over 40 could be charged a lot more.
Without a requirement to buy insurance, the Senate bill provides no reason to sign up for insurance before coverage is needed.
“There needs to be provisions to discourage people from waiting until they get sick to buy insurance,” said Karen Ignagni, the chief executive of EmblemHealth and the former head of America’s Health Insurance Plans, a trade group. The absence of any penalty for not having insurance could cause some markets to fall into a death spiral as prices rise and drive out the healthy.
“We don’t have to speculate about it,” Ms. Ignagni said, pointing to a number of states, like New York, where insurance was virtually unavailable because of the high costs before the Affordable Care Act.
In Pennsylvania, the state insurance regulator, Teresa D. Miller, warned that insurance rates could be at least 23 percent higher without the individual mandate. While the proposed bill could lower rates by funding the cost-sharing reductions for the next year or so, other provisions have the opposite effect. “With everything else going on in this bill, I don’t think it’s going to be that stabilizing force people might want it to be,” she said.
The changes are likely to result in fewer people being covered, and those people could be much sicker, said Dr. Stephen Ondra, a former insurance executive who worked under the Obama administration. “The insurance company has no choice but to set rates based on the risk pool they have, not the one they like,” he said.
Insurers were beginning to get a handle on the market, he said, but the uncertainty and the changes under the Senate bill could lead to more companies deciding to leave. “This is a crisis that has been created by uncertainty and proposed legislation, not a failure of the A.C.A. markets,” Dr. Ondra said.