Updated at 11:55 a.m. with comments from Yale Medicine.

Yale Medicine, the medical practice that includes more than 1,400 Yale School of Medicine clinical faculty physicians, could leave Anthem Blue Cross and Blue Shield’s network next month if the two organizations don’t reach a contract agreement.

The dispute pits Connecticut’s largest insurer against a major group of clinicians, and could affect thousands of patients.

Anthem says Yale Medicine told the insurer it plans to terminate its contracts if they don’t reach an agreement by Oct. 7. If that happens, Anthem customers would still be able to see Yale Medicine providers, but could face higher costs because the care would be considered out of network. (There are some exceptions: Emergency care would still be covered, and in some cases, patients receiving active treatment could arrange to have their ongoing care covered as if it were in the insurer’s network.)

Yale Medicine – formerly known as Yale Medical Group – describes itself as one of the largest academic multispecialty group practices in the country. The negotiations do not affect Yale-New Haven Hospital or the Yale New Haven Health System, including the health care providers who are part of the system’s Northeast Medical Group.

Contract terminations have become more common in negotiations between hospitals and insurance companies in recent years. Most have been resolved before the hospitals left the network, although in some cases, hospitals have briefly left insurer networks. In 2012, Connecticut Children’s Medical Center left Anthem’s network for two months before the two sides reached a new contract. And in 2014, five hospitals owned by Hartford HealthCare left Anthem’s network for one day before a deal was reached.

A statement from Anthem said Yale Medicine is seeking “a considerable rate increase.”

“Anthem understands that our customers and members value both access to Yale Medicine and health care affordability,” the statement said. “Anthem will continue to work hard to retain Yale Medicine in our network in a manner that balances both of these interests.”

If the contract is terminated, the company said, “Anthem will closely monitor the effects of these terminations on our members, employer groups, physicians and other providers and will retain our focus on helping our members find the right care, from the right providers, in the right setting.”

Yale Medicine said in a statement that it is still negotiating with Anthem and hopes to maintain the relationship.

“However, our current contract with Anthem does not fairly reflect the reality of the value we provide,” the statement said. “As a result, Yale Medicine is requesting an adjustment in Anthem’s payment rates as part of a multi-year agreement. Securing a new contract from Anthem is critical to our long-term financial and operational sustainability.”

And Yale Medicine said contracts with major insurers have a major impact on its ability to provide quality care, allowing it to recruit and retain top doctors and staff, purchase new technology and expand.

Although the two sides could reach an agreement before the deadline, Demian Fontanella, the state’s acting healthcare advocate, said some patients should begin making plans now, just in case. A possible network change would likely most affect people who are in an active course of treatment or who have appointments scheduled with specialists, he said.

His advice?

“Start planning now, especially if you have chronic ongoing or intensive needs that an interruption of even a couple weeks or a month would be problematic for your treatment or your prognosis,” Fontanella said.

That means talking to care providers to find out what to do to maintain the treatment or identify other options, and get and fill out Anthem’s form for continuity of care.

And Fontanella said people should get in touch with his office – the state Office of the Healthcare Advocate – or their insurer or medical provider if there are problems. Anthem has a responsibility to ensure that patients have access to care in a timely manner and a relatively proximate distance from their homes, Fontanella said, but he added that patient rights can be nuanced and challenging to understand when issues of timeliness and distance are involved. During the two-month period when Connecticut Children’s was outside Anthem’s network, he said, the advocate’s office was involved with approximately 800 cases.

Fontanella expects the two sides to reach an agreement at some point; it’s not economically feasible for either side not to have a contract with the other, he said. But he said contract disputes that lead to potential terminations are likely to become commonplace as insurance companies and health care providers face more financial pressure. And increasing consolidation among medical providers, along with a health insurance market with relatively few players, means all parties have the leverage to demand more, he said.

Anthem is one of two insurers that will sell health plans through the state’s insurance exchange, Access Health CT, next year, and open enrollment begins in November. Asked if he had concerns about the potential for one of the two carriers to not include a major New Haven-area medical group, Access Health CEO Jim Wadleigh said it is up to the insurers and the state’s insurance department to ensure that the networks meet adequacy standards.

Wadleigh said people should view provider-insurer contract disputes in context of health care costs, including rate hikes for 2017 that have drawn criticism in recent months.

“Everyone’s quick to blast the carriers for asking for rate increases, but I’m not sure everyone right now is seeing the impact of the hospitals requesting higher rates; now the providers are asking for higher rates,” he said. “I want to make sure everyone sees the big microcosm here of how everything is inflating the cost of health care.”

Connecticut Insurance Department spokeswoman Donna Tommelleo said the agency will ensure that Anthem’s communication “clearly informs its members on continuation of care for those in active treatment and information on other in-network providers in the area who can meet their health care needs.”

Click here for a Q&A by Anthem for members.