To help pay some for some of your out-of-pocket health care costs, you can buy Medigap insurance, also known as Medicare Supplement Insurance.

There’s one important distinction to make: A Medigap policy isn’t the same as a Medicare Advantage Plan, which is a health plan offered by a private insurance company that contracts with Medicare. Prescription drug coverage, hospital insurance and medical coverage are included.

“Not everyone should consider buying a Medigap policy,” said Bob Moos, spokesman for the Centers for Medicare & Medicaid Services. “You don’t need to supplement your Medicare coverage if you’re on Medicaid or signed up for a private Medicare Advantage plan or enrolled in a group health plan through an employer or former employer.”

There are 10 kinds of Medigap plans, so you can choose which gaps you’d like to fill.

Because each standardized Medigap policy must offer the same basic benefits, cost is usually the only difference among policies.

Here’s how to shop:

COMPARE PREMIUMS

For example, annual premiums for a nonsmoking 65-year-old for Plan F, the most popular Medigap plan, range from $1,097 to $4,030, according to the Texas Department of Insurance. Your premium will depend on your individual circumstances.

Each insurance company decides how it will set a Medigap policy’s premium, so ask how an insurance company prices its policies.

Medigap policies can be priced in three ways:

• Community-rated. That means that generally, the insurer charges the same monthly premium to everyone regardless of age. However, premiums may increase because of inflation and other factors.

• Issued-age-related. The premium is based your age when you buy the Medigap policy. Premiums are lower for people who buy when they’re younger and won’t change as you age. But prices may go up because of other factors.

• Attained-age-related. The premium is based on your age and rises as you get older. Premiums may be the least expensive at first, but they can eventually become the most expensive. They may also go up because of other factors.

Beyond researching the initial price, find out how often an insurer has raised premiums.

“That’s the second-biggest piece they should focus in on,” said Chris Renfro, owner of Next Generation Insurance Services in Dallas, a health insurance brokerage company. “What is the historical rate increase of that policy from year one to year two to year three and on up? What’s their philosophy on rate increases?”

An insurance broker would have that information.

SELECT YOUR BENEFITS

Consider your current and future health needs in deciding which benefits you want, because you might not be able to switch Medigap policies later.

For example, do you or your spouse need skilled nursing care? If so, you want a policy that will help cover those costs. Do you travel overseas frequently? You may want a policy that covers emergencies when traveling.

Note that if you and your spouse both want Medigap coverage, you must buy separate policies.

Also, some Medigap policies sold in the past cover prescription drugs, but those sold since Jan. 1, 2006, aren’t allowed to.

If you want prescription drug coverage, you can join a Medicare Prescription Drug Plan (Part D). These plans are offered by insurance companies and other private companies approved by Medicare.

ACT PROMPTLY

If you’re buying a Medigap policy, be sure to do it within six months of turning 65 and enrolling in Medicare’s Part B medical insurance.

“During that time, insurers can’t refuse to sell you a policy, or charge you more than other people, because of a health problem,” Moos said. “If you try to buy after those six months, there’s no guarantee an insurer will cover you.”

It’s also wise to read your Medigap policy as soon as you receive it. If you’re not satisfied, you have 30 days to return it and get a full refund. Otherwise, you can keep your insurance as long as you pay your premiums.

CHECK THE RECORD

You can buy a Medigap policy from any insurance company that’s licensed in your state to sell one.

Be sure to check out an insurer’s customer service performance before buying.

“Medigap insurance doesn’t plug all the holes,” Moos said. “It’s not a way to pay for long-term custodial care, dental care, eyeglasses or hearing aids. And new Medigap policyholders need to buy separate drug coverage under Medicare’s Part D if they want it.”

Still, he said, “for many people, adding a Medigap plan to traditional Medicare coverage can make out-of-pocket health care expenses more predictable and easier to budget.”

Pamela Yip is a personal finance columnist for the Dallas Morning News. Email: pyip@dallasnews.com; she cannot make individual replies.