A postelection survey of primary care physicians reveals that majorities of the doctors that first treat most Americans do not support some of the GOP’s most widely circulated plans to repeal and replace the Affordable Care Act.

Conducted in December and January and published online Wednesday in the New England Journal of Medicine, the new survey shows that nearly three-quarters of general practitioners favored making changes to the Obama administration’s signature health care reform measure.

But in this nationally representative sample of primary care doctors, only 15 percent favored the law’s repeal. Among responding physicians who voted for Donald Trump, only 38 percent favored the law’s repeal.

That makes the repeal of the Affordable Care Act, also known as Obamacare, far less popular among the physicians on the front lines of medicine than it is in the American body politic. A Kaiser Family Foundation poll taken after the November 2016 election found that 26 percent of Americans wanted to see Obamacare repealed.

Like President Donald Trump, primary care doctors were aligned solidly behind a continued guarantee of access to insurance irrespective of patients’ pre-existing conditions (95.1 percent approved). And a broad majority (87.6 percent) said they supported a provision of the health care law that allows young adults up to 26 to stay on their parents’ insurance plans.

Beyond that, however, the survey uncovers scant support for many proposals that have emerged as leading Republican alternatives to the health care law’s provisions. As lawmakers debate the details, many of their proposals would shift health care costs toward patients, pare some benefits and extend less financial help for many who could struggle to afford insurance coverage.

But among primary care docs, just 29 percent expressed support for measures that would expand the use of health insurance plans with high deductibles.

Some 42 percent of respondents said they oppose further deregulation of private insurance markets. Among the most visible GOP deregulation proposals now circulating is a plan to allow insurance companies to sell policies across state lines.

And 58.6 percent expressed support for tax credits to help Medicaid-eligible people purchase private insurance policies.

Among the survey’s most striking findings was strong support for an extension of the Affordable Care Act that is absent from any GOP proposals: Two-thirds of primary care physicians endorsed the idea that any health care reform should include a public insurance option resembling Medicare that would compete with private plans.

Study co-author Dr. Craig Evan Pollack, an internal medicine specialist at Johns Hopkins University School of Medicine, said he was struck by the strength of physicians’ opposition to measures that increased complexity and shifted costs toward patients. He suggested it was a direct result of doctors’ experience in caring for patients.

“As physicians, we see people struggle with out-of-pocket costs, deciding which types of care they’re able to afford and making very challenging decisions,” said Pollack. Primary care physicians, he added, “try to advocate for their patients.”