Minnesotans who lost their Medicare Cost health plans for 2019 are nearing the end of extra sign-up periods when they can make changes, prompting state officials to encourage final checks among the more than 300,000 people who had to switch coverage.

A Star Tribune review of January enrollment data shows that most Minnesotans didn't select a "zero-premium" health plan, which suggests many paid more up front in hopes of minimizing problems with limited access to doctors or less coverage for their prescription drugs.

Even so, trouble with physician networks and medication costs are two reasons that more than 1,500 people have contacted the state for help switching Medicare plans, according to the Minnesota Board on Aging. The agency says the tally is about 50 percent higher than last year.

"There is a considerable number of people who have found out the plan they chose for January 1 is just not working for them," said Kelli Jo Greiner, health policy analyst with the state agency. Noting that the first of three deadlines for switches is coming Feb. 28, Greiner said: "Check to make sure that the plan that you enrolled in is going to work for you, because you have a limited amount of time in which to change."

Minnesota's Medicare market is undergoing a large shift after a federal law eliminated Medicare Cost health plans across 66 counties this year. Those forced out of their health plans faced a choice between original Medicare and Medicare Advantage plans sold by private health insurers.

Most seniors tend to stick with Medicare coverage from year to year, so the shift set off a competitive frenzy among health insurers.

For Minnesotans who've found their new coverage isn't working well, three deadlines for making changes are coming quickly.

Seniors who lost their Cost plans and are supplementing original Medicare with a stand-alone Part D prescription drug plan have until Thursday to pick a different Part D plan, according to the Minnesota Department of Commerce. Those who lost Cost plans have until March 4 to buy a Medicare Supplement, or Medigap, insurance policy without having to answer questions about their health history — a process known as "medical underwriting" that sometimes prompts carriers to not offer coverage.

Finally, any Medicare beneficiary who enrolled in a Medicare Advantage health plan for 2019 has until March 31 to switch to a new Medicare Advantage plan. Or, they can return to original Medicare and sign up for a stand-alone Part D plan.

The Minnesota Board on Aging said that between Jan. 1 and Feb. 11, the state's Senior LinkAge Line helped 1,572 people switch Medicare coverage, up from 1,050 switches during the same period last year.

Prescription drug coverage is a key variable with health plans for seniors because so many on Medicare routinely take medications. So, if people selected a health plan that required much higher costs for their medications, those problems likely showed up quickly in January, said Greiner of the Minnesota Board on Aging.

If the new coverage requires higher payments at the doctor's office because the clinic is not in-network, the change might not yet be apparent to seniors who haven't visited the doctor in the new year. Seniors can check on the network status of their health care providers by contacting their doctor's office, calling their new health insurer or checking the health plan's online directory of health care providers.

"We are busier than we usually are after open enrollment ends," Greiner said.

Neither Bloomington-based HealthPartners nor Minnetonka-based Medica say they've seen many cases of consumers switching coverage thus far. But Minneapolis-based UCare has been hearing from consumers who are considering a change because they've found their new coverage doesn't include access to certain doctors and hospitals at in-network rates, said Ghita Worcester, a senior vice president with the health insurer.

Eagan-based Blue Cross and Blue Shield of Minnesota says it's seen a net increase in Medicare enrollment of about 4,500 people during 2019, with most activity coming from people moving into Medigap plans. The insurer says that many Cost plan enrollees found the closest fit to their old coverage is original Medicare plus a Medigap supplemental plan plus stand-alone Part D drug coverage.

Going the Medigap plus Part D route typically involves higher premiums and lower out-of-pocket costs than Medicare Advantage plans, which in some cases don't even charge a monthly premium. Across the country, these "zero-premium" plans account for about half of all Medicare Advantage plans sold, according to the Kaiser Family Foundation.

But a Star Tribune review of January enrollment data shows zero-premium plans have been much less popular in Minnesota, with only about 5 percent of state residents who enrolled in a Medicare health plan opting for the coverage. Greiner said her group's analysis of federal data came to the same conclusion; the relatively low interest in zero-premium plans showed up again in recently released figures for February, she said.

There were no zero-premium Cost plans, so people losing the coverage often were simply looking to hold their premium payment steady for 2019, said Tom Lindquist, a senior vice president with Medica.

With higher premiums, Cost plans had relatively rich benefits that didn't trigger big out-of-pocket costs when people used health care. So, Medicare shoppers facing a change looked for that sort of coverage among the remaining options, said Doug Smith, a senior vice president at HealthPartners.

A third factor is that the federal government pays Medicare Advantage plans different rates in different parts of the country, said Worcester of UCare. Insurers in Minnesota have been on the low end of the payment spectrum for years, she said, so the benefits that come with a zero-premium product in the state aren't as rich as health plans in high-payment states like Florida.

Data editor MaryJo Webster contributed to this report.

Twitter: @chrissnowbeck