Correction: A previous version of this story stated incorrectly that an appeals court in Texas upheld an order to prohibit such terminations, similar to an injunction by a federal judge in Connecticut. There is no such case in Texas; the Texas Medical Association was among the groups from other states filing friend-of-the-court briefs in the Connecticut case. This version has been corrected.

Thousands of primary-care doctors and specialists across the country have been terminated from privately run Medicare Advantage plans, sparking a battle between doctors who say patient care is being threatened and insurers that insist they have to reduce costs and streamline their operations.

Medical associations, which describe the dismissals as the largest in the program’s history, say the cuts are forcing some patients to leave their doctors in mid-treatment and creating gaps in the types of medical specialists covered in some areas. They’re taking their protests to court, and having some success.

In December, a federal judge in Connecticut issued an injunction that temporarily prohibits an insurer from dismissing doctors in Fairfield and Hartford counties. Another lawsuit is pending in New York, and doctors groups in several other states are threatening legal action.

The American Medical Association, the nation’s premier doctors organization — along with 39 state affiliates and 42 patient and medical specialty groups — has called on the Obama administration to intervene and put pressure on insurers to reverse the terminations.

Insurers say they must shrink their physician networks because they face billions of dollars in government-payment cuts over the next decade — reductions that are being used partly to fund insurance coverage for millions of people under the federal Affordable Care Act. They also say the smaller networks will allow them to curb premium increases and to remain nimble as they prepare for an influx of patients under the law.

Medicare Advantage, an alternative to traditional Medicare, covers 13 million beneficiaries, or 27 percent of the people in the federal health-care program for the elderly. Besides providing the standard benefits, the thousands of Medicare Advantage plans often offer extra perks such as free eyeglasses and adhesive bandages. They can do that because, for years, the government has paid the plans more, per patient, than it spends on regular Medicare.

That has been a sore point for Democrats, who used the health-care law to cut payments to Medicare Advantage by $156 billion over the next decade.

Notification complaints
The doctor terminations, most of which took effect Jan. 1, are striking a nerve partly because of the way insurers have notified some physicians.

Arthur Vogelman, a gastroenterologist, received a letter in the fall from United Healthcare informing him that he had been dropped from the insurer’s physician network. He said the letter contained no information about the reason for the termination. He appealed to the company and documented his successful treatment of thousands of patients, but his request was denied with no reason given.

“It is an outrage. I have patients in their 80s and 90s who have been with me 20 years, and I’m having to tell them that their insurer won’t pay for them to see me anymore. The worst thing is I can’t even tell them why,” Vogelman said.

One of his patients, Jorge Otoya, 68, who is retired from Morgan Stanley’s trading desk, said he had tried, without success, to find a plan that includes both Vogelman and his primary-care doctor at New York University.

“I am a cancer survivor and have been going to this doctor for 15 years,” Otoya said. “He knows my system, left and right. I trust him. I called United Healthcare to protest, but they didn’t care.”

Medical associations say a number of insurers are trimming their networks this year, but the most dramatic reductions may be occurring in United Healthcare’s Medicare Advantage plan. With 3 million members, the AARP-endorsed plan is the largest of its kind in the nation.

United Healthcare said that it aims to reduce its national network of physicians by 10 to 15 percent by the end of 2014. The company declined to provide specific numbers, but medical associations say that in some states, thousands of doctors have been cut.

Jack Larson, United Healthcare chief executive for Medicare and retirement, said in an interview that he believes the smaller networks will lead to better patient care, because insurers will be able to work more closely with doctors.

“I’m not diminishing at all the short-term disruption when someone loses access to their physician. That’s a hard thing. . . . But we do believe that to have a quality health-care system we need to seek those physicians who have exceptional quality related to cost,” Larson said.

A few weeks ago, the insurance industry, led by America’s Health Insurance Plans, a trade group, launched a public-awareness campaign that includes TV, print, digital and display ads and encourages seniors, a group with substantial political clout, to write and Tweet about their concerns over the payment cuts. Industry officials have been appearing on Sunday talk shows and pressing lawmakers to restore some of the funding.

A spokesman for the federal Centers for Medicare and Medicaid Services said that the agency is reviewing information about affected areas of the country but that health plans are allowed to change their networks at any time of year, as long as they provide adequate notice to providers and patients.

Doctors who have been cut from the networks say they are angry and confused about the sudden terminations, how they were communicated, the possible damage to their reputations, and the financial effect on their practices.

Some doctors say they did not receive letters informing them that they were no longer part of an insurer’s network. Others say their patients were told before they were.

“The way this was handled was completely wrong,” said Patricia McLaughlin, an ophthalmologist in Manhattan. She discovered that she had been cut from one plan’s network when she was searching for doctors online for her own family and noticed that she was no longer in the company’s provider database.

She added that because insurers haven’t been forthcoming about why some providers were cut and others were not, the terminations have made for awkward conversations with patients. “Many patients don’t understand that this isn’t their doctor’s fault, and that’s just despicable,” McLaughlin said.

Difficult choices

The terminations have forced doctors to make difficult decisions about how to handle longtime patients whose insurance will no longer pay for the doctors’ services.

Vogelman’s office is canceling appointments made by his 143 patients enrolled in United Healthcare’s Medicare Advantage plan, because, he explained, “I won’t get paid.” He is referring those patients to doctors he trusts.

Vlad Fridman, a Brooklyn cardiologist who was also cut from United Healthcare’s network, is taking a different approach. His practice decided to waive the customary $100 fee for the 100 or so existing patients enrolled in that plan. But Fridman said he’s not sure how the details will work out, whether the plan will cover tests his practice orders or what will happen when patients have to be hospitalized.

“Honestly, we are telling those patients we will see them for free. It’s just fair. Me and my partner have been seeing them for years” Fridman said. “But the rest of it I have no control over, and we are at a loss about what to do.”