ObamaCare is making seniors sick.

Elderly New Yorkers are in a panic after getting notices that insurance companies are booting their doctors from the Medicare Advantage program as a result of the shifting medical landscape under ObamaCare.

That leaves patients with unenviable choices: keep the same insurance plan and find another doctor, pay out of pocket or look for another plan where their physician is a member.

New York State Medical Society President Sam Unterricht is demanding a congressional probe after learning that one health carrier alone, UnitedHealthcare, is terminating contracts with up to 2,100 doctors serving 8,000 Medicare Advantage patients in the New York metro region.

The are 2.6 million elderly New Yorkers who receive Medicare, the public heath-insurance program for the elderly.

But one in three patients — nearly 900,000 — are enrolled in Advantage, Medicare HMOs run by private insurers.

Dr. Jonathan Leibowitz, who serves 30 patients under Medicare Advantage at his Brooklyn practice, said he was blindsided by UnitedHealthcare’s decision to give him the boot.

“A patient can’t see his doctor? What are they doing!” he asked.

UnitedHealthcare told Leibowitz that because of “significant changes and pressures in the health-care environment,” he’d be getting the ax on Jan. 1.

Leibowitz’s patients are furious. Alfred Gargiulio, who has cerebral palsy with a seizure disorder, has been seeing Leibowitz since 1993. “Obama had said I could keep my doctor. Now they’re doing away with my doctor. They kicked him out! After 20 years, that’s not right. We love Dr. Leibowitz,” said Gargiulio.

Another patient, Wilma Streicher, 76, was equally baffled. “Of course I want to keep Dr. Leibowitz. I don’t see why they want to push him out,” she said.

Patients of other doctors faced the same dire situation. Lung-cancer patient Jeannette Campregon, 79, received a letter from EmblemHealth saying that her internist, George Ruggiero, was terminated from her VIP High Option Medicare Advantage network.

Emblem notified her she could stay in her current plan and choose another doctor, pick a different plan to keep her doctor or call a customer-service rep for help.

“I’m going absolutely nuts,” said Campregon, who got conflicting information from three different service reps. “I don’t want to change my doctor!”

Dr. Ruggiero said, “The people who lose out are the patients.”

Federal funding to Medicare Advantage is being pared back by billions of dollars in coming years under the national Affordable Care Act. Obama said spending on the program was higher than regular Medicare and unsustainable.

UnitedHealthcare, in a statement, defended the doctor-roster cuts.

“The changes we are making will encourage higher-quality health-care coverage and help keep that coverage affordable for [patients],” said UHC spokeswoman Maria Gordon-Shydlo.

A spokesman for Emblem said the less than 1 percent of its physicians were being cut from Medicare Advantage.

An Empire Blue Cross-Blue Shield rep also said it booted “only 1 percent of doctors.”

“Those physicians were in certain specialties, including cardiology, ophthalmology and podiatry. This was done to ensure a more balanced network that would better contain cost for members,” said Empire spokeswoman Sally Kweskin.

An official with the state chapter of AARP said it’s monitoring the “horrible situation.”

AARP Associate Director Shaun Flynn said Medicare Advantage is a popular program but cautioned it’s privately run, and insurers — not patients — decide which doctors participate.

‘It’s a case of buyer beware,” he said.