Seniors are the biggest consumers of the country s health care system in terms of dollar amount and volume. They generally take more prescription drugs, visit the doctor more often and stay in the hospital more frequently than the average patient. So they would be most impacted by any overhaul of the health-care system.

They re also the group that s reported feeling most confused by the debate over reform.

Overall, 62% of people over 65 say they re confused about health-care plans being considered by Congress compared with 43% of those under age 65, according to an August poll by Kaiser Family Foundation, a health policy nonprofit research group. And less than a quarter of seniors polled believe reform would benefit them or their families compared with 39% of those under 65.

Much of the unease stems from potential changes to Medicare, a program used by about 15% of the population that accounts for 22% of total personal health-care spending.

More debate over the legislation is expected once Congress returns from its summer recess after Labor Day. President Obama is expected to lay out a more specific blueprint for what he wants out of the plan as early as next week.

In the meantime, here s a look at how the current proposals would change health care for older Americans.

1. Savings for seniors in the doughnut hole

Premiums for drugs could rise as much as 20% over the next decade, according to a letter released last week by the Congressional Budget Office (CBO) addressing potential reform tweaks to Medicare Part D, the program that subsidizes prescription drug costs. Despite a rise in premiums, overall spending on prescription drugs would fall, on average, the CBO says.

The House bill would effectively increase premium costs because it is designed to end an existing gap in Medicare drug coverage known as the "doughnut hole." Currently, about a quarter of Medicare patients with prescription drug coverage fall into this hole. Once the cost of a patient s prescriptions exceeds about $2,700 (for 2009), they have to cover the next $4,350 on their own (once beneficiaries hit $4,350 in out-of-pocket costs, catastrophic coverage kicks in and they pay only a nominal amount per prescription). The House bill would gradually narrow that gap until it would be eliminated in 2022. And before then, beneficiaries in the doughnut hole would get a 50% discount on certain brand-name drugs.

2. Some seniors will pay more

Eliminating the doughnut hole would reduce out-of-pocket costs of most Part D beneficiaries, says Tricia Neuman, the director of the Medicare Policy Project at the Kaiser Family Foundation. However, the effect on a patient s total spending would vary based on their care.

Though they may be in the minority, some seniors have minimal drug needs and never reach the doughnut hole. They ll likely lose out under the legislation and end up paying more in additional premiums than they would gain from lower cost sharing.

Under current law, doctors are scheduled to see an across-the-board 20% cut in the fees they can charge Medicare patients next year. The House bill would essentially repeal this reduction by providing more funding for payments to physicians, says Chris Conover, a public policy research scholar at Duke University s Center for Health Policy.

That part of the bill is designed to prevent a surge in the number of doctors unwilling to see Medicare patients. So relative to the status quo, this isn t a big deal. But had [Congress] not made this fix, it likely would have been a huge deal, says Conover. A bill without this provision (or a bill that fails to pass Congress) could leave seniors with fewer doctors and, by extension, limited access to medical care.

4. Cuts to Medicare Advantage program

There are two basic ways seniors get Medicare coverage. Roughly 80% enroll in a traditional Medicare and prescription drug program. The rest use one of several Medicare Advantage programs, which are run by private insurers. Advantage plans get federal subsidies and typically have more generous benefits like dental and vision coverage.

The plans now cost the government about 14% more per person than regular Medicare, according to an analysis by the Medicare Payment Advisory Commission, an independent Congressional agency. The House legislation would scale back payments to Advantage plans and would save $156 billion over 10 years, according to the CBO.

The potential impact of these cutbacks on beneficiaries is a source of some resistance to reform. But no one knows yet how private insurers will respond to a change in those federal subsidies. Companies could decide to end their programs if they don t feel they can operate them profitably, says Neuman. Or they may cut back on extra benefits or increase premiums or cost sharing.

Any of those changes would trouble seniors using the Advantage program. They ll lose the plans they had come to like, Conover says.

5. Longer wait times at the doctor s office

One goal of reform is to expand health care access to the 47 million uninsured Americans. Say a typical person without coverage gets 50% to 60% of the care of a traditionally insured person. If legislation passes granting these people coverage, then all of a sudden, you ll essentially double their utilization, Conover says. And that may affect all consumers access to care.

We haven t changed the number of providers, so it s sort of obvious there will be longer waiting times, which will affect everybody, Conover says. To the degree that the elderly are disproportionate users of the health-care system, they ll feel it more. The problem will be more acute in states where the uninsured rate is higher like in Texas because demand for care will rise that much more relative to the rest of the population, he says.