UPDATE: Anthem leaving Obamacare exchanges in Ohio

One of the nation's biggest health insurers says it will not return to Ohio's public insurance exchanges next year, a decision that could open more holes in the Affordable Care Act's increasingly thin system for helping people buy coverage.

The move announced Tuesday by Indianapolis-based Anthem Inc. could leave shoppers in 20 counties without an option for buying individual coverage on the exchange unless another insurer steps in, according to data compiled by The Associated Press and the consulting firm Avalere.

The exchanges are the only place where people can use an income-based tax credit to help cover the cost of coverage.

Insurers are finalizing their plans for next year, and exchange choices have grown sparse in many markets around the country. While several insurers have said they plan to return for 2018 and metropolitan markets are expected to still have several choices, national companies like Humana and Aetna have already decided to leave the on-exchange market entirely.

Another insurer, Blue Cross and Blue Shield of Kansas City, said late last month that it also was leaving the exchanges, a decision that could leave 25 counties in that market with no on-exchange options. People may be able to find options off the exchange there but without the benefit of a subsidy to help pay for coverage.

Many insurers, like Anthem, have said they are worried about the future of the exchanges, which generally make up a small slice of their business but have generated steep losses for them and soaring prices for many customers.

Anthem Inc. said Tuesday that it is concerned about the possible restoration next year of a tax on insurers and a lack of certainty for cost-sharing reduction payments.

The government has been giving insurers money to help customers with modest incomes cover out-of-pocket expenses like co-payments and deductibles. But the future of those payments, which are separate from the income-based tax credits that help people buy coverage, is in political limbo. President Donald Trump has talked about potentially stopping the payments, and insurers want a guarantee that they will last through next year.

Congressional Republicans also are working on plans to replace the Affordable Care Act.

Trump administration spokeswoman Alleigh Marre said Tuesday that Anthem's decision in Ohio "is a stark reminder that Obamacare is collapsing."

But the second-ranking House Democrat blamed the market instability on the Trump's administration's actions. Rep. Steny Hoyer, D-Md, said, "Instead of holding insurers and consumers in limbo, Republicans ought to end this TrumpCare charade and work with Democrats to restore stability."

Health care researchers have said they don't expect the exchanges to implode, even though coverage holes will develop in rural markets. Those areas often have trouble drawing insurers due to unattractive qualities, like a smaller, older population and hospitals or other health care providers with a dominant market position.

Most of the 20 Ohio counties that could be left with no exchange options for next year are in rural areas, according to the AP and Avalere data. About 15,000 people are enrolled in insurance coverage through the exchange in those counties.

Overall, Anthem covers more than 1 million people through the exchanges nationally and is considered a key player in determining their future. It offers Blue Cross-Blue Shield coverage in huge markets like New York and California.

Anthem said earlier this year that it was planning to return in 2018. But company leaders indicated that could change if they don't get some certainty by early June on the cost-sharing payments.

An Anthem spokeswoman said Tuesday that the company was still talking with regulators in other states.