As if there isn't enough to worry about when it comes to finding health insurance, add this item to the list: Medicare Advantage.

Changes in plan structures and a dearth of insurers in rural areas may leave consumers with fewer choices and more confusion in the upcoming Medicare open enrollment period, which begins October 15.

Medicare Advantage plans, offered by private insurers, provide traditional Medicare coverage and often offer additional benefits such as dental, vision and Medicare Part D prescription drug coverage. Premiums, deductibles and co-pays vary significantly from plan to plan, so comparing costs and coverage each year — even if you are already enrolled — is critical.

Medicare Advantage is different from Medigap, which is designed to help fill the gaps in traditional Medicare coverage.

In the recent past, some Medicare Advantage plan members have been struggling to find the care they need, especially those who have acute or chronic illnesses. About one-third of people eligible for Medicare enroll in Advantage plans. A recent Government Accountability Office report found that a large number of Medicare Advantage enrollees, especially those in poor health, drop out of the plans because they have trouble getting access to the care they need. Of the 126 Medicare Advantage plans studied, the GAO found 35 of them had disproportionately high numbers of sick people dropping out.

If you are part of a Medicare Advantage plan or considering Medicare Advantage in the upcoming sign up period, or if you are taking care of a loved one with MA coverage, here's a preliminary glimpse at what you need to watch out for in the year ahead.

Look for changes in your existing plan. If you're already enrolled in a Medicare Advantage plan, your insurer will likely send you information soon regarding 2018 plan details. Read this carefully. "Just because a plan works for you this year doesn't mean it will necessarily work for you next year." warned David Lipschutz, an attorney at the Center for Medicare Advocacy. Many insurers change their cost-sharing, premiums and prescription drug formularies (the list of drugs covered by the plan) each year, Lipschutz explained. Look closely at any changes your plan is implementing and compare that to other plans available in your area. Existing Medicare enrollees and first-time shoppers can compare Medicare Advantage plans and traditional Medicare on Medicare.gov.

Check your health network. Like all health insurance plans, Medicare Advantage insurers negotiate with hospitals, doctors and other health care providers to find the lowest cost providers each year. Those networks — both health maintenance organizations and preferred provider organizations — are subject to change every year. In recent years, these provider networks have become smaller, with fewer specialists. These changes were among the main reasons Medicare Advantage enrollees dropped out of their plans, according to the GAO report. Always check to make sure the network on your plan or the plans you are considering include the providers you need to stay healthy. And check to see if more of the providers you need are available to you through traditional Medicare.

Rural consumers may be out of luck. Much has been said about rural counties left with only one or no insurance options on the Obamacare exchanges. State insurance commissioners, insurers and others have been working hard to successfully fill those gaps. In the meantime, the real dearth of coverage may exist among Medicare Advantage insurers. According to a recent report from the Kaiser Family Foundation, 147 counties, across 14 states have no Medicare Advantage insurer this year.

If you live in an area with no Medicare Advantage insurer you'll need to take the time to thoroughly understand traditional Medicare coverage and decide if a Medigap policy is right for you.

Get help while you still can. Your State Health Insurance Assistance Program (SHIP) can help you sort through your Medicare options and compare Medicare Advantage plans. SHIPs are funded through the federal government and provide free health care counseling for Medicare recipients. The Trump Administration's budget proposal would cut funding for SHIPs entirely, Lipschutz said. He suggested starting your health plan search now while this resource is still available. To find the SHIP in your state, click here.