Premiums will hold steady for many, but out-of-pocket costs are rising.

Insurers may be shifting toward cutting monthly premiums by increasing out-of-pocket costs in the Medicare Part D prescription drug plan market.

Analysts at Avalere Health looked at 2015 Part D plan data from the Centers for Medicare & Medicaid Services and found that the total number of Part D plans available will fall 14 percent, to 1,001.

Big players like Aetna, Cigna, CVS and UnitedHealth are reducing the number of prescription plans they offer, and focusing mainly on offering plans with average monthly premiums below $30, the analysts report.

In 2015, only two of the 10 plans with the highest enrollment will have an average monthly premium over $50.

The average monthly premium for all plans will fall 2 percent, to $38.95, and the average for the top 10 plans will fall 6 percent, to $36.39.

Meanwhile, as the premiums fall, out-of-pocket costs are rising. The share of Part D plans with no deductible will fall to 42 percent, from 47 percent.

The Avalere analysts also took another look at the Medicare Advantage plan data, on a county-by-county basis. They found that the average number of plans is falling in some Mid-Atlantic counties and parts of New England but increasing in most of the rest of New England, and in many counties in California, Idaho, Illinois, Kentucky, Louisiana, Michigan, Montana, Oklahoma, Tennessee and Wisconsin.

See also: 5 things you have to know about 2015 private Medicare plans