CHICAGO - Medicare crises, looming doctor shortages, more patients without health insurance. And that doesn't even count the big changes coming from a revamped health care system.

It's a troubling time for doctors as they gather for the annual American Medical Association meeting.

The group's president, Dr. Cecil Wilson, is an avid sailor, and he says his hobby has served him well in navigating these uncharted, murky waters.

An internist in Winter Park, Fla., Wilson told The Associated Press this week that the nation's health care system "is sick, and that's why we've gone through this agony developing health care reform. We've got to make it better."

His yearlong term as AMA president ends Tuesday during the group's 160th annual meeting, where it votes on policy measures to adopt and lobby for. But new challenges are just beginning for doctors as the Obama administration's Affordable Care Act starts kicking in.

"The ground is shifting under our feet," said Dr. Jacqueline Fincher, a primary care doctor in rural Thomson, Ga. "We're all anticipating and hoping for the best and preparing for the worst."

Some of those challenges will be debated at the AMA meeting, which starts Saturday in Chicago. Doctors who oppose the Affordable Care Act want the AMA to revoke its support. The AMA is unlikely to change its stance on health care overhaul in voting that begins Monday, but Wilson stressed that the group views reform as something that can be tweaked and made better.

"This law is not the final step - it's the first step for overhaul of the system," he said.

Other measures on the AMA meeting agenda include proposals asking the group to support a ban on synthetic recreational drugs sometimes called "bath salts" that have sickened thousands; to study the safety of airport body scanners; and to declare that prohibiting gay marriage is discriminatory.

But the same haze of uncertainty and anticipation hanging over the entire industry is certain to pervade the meeting as doctors try to figure out what the upcoming reforms mean for them.

"There's a lot of anxiety about how our practice is going to change," said Dr. Kevin Pho, a blogger and primary care doctor in Nashua, N.H.

Dr. Vineet Arora, who works in medical education at the University of Chicago and plans to attend the meeting, said students and doctors-in-training have lots of questions "but it's hard to know what the system is that they're going to inherit."

Arora supports reform's major push to get millions more Americans health insurance coverage, but worries that there won't be enough primary care doctors to treat all those patients when that provision begins in 2014.

Many students she has worked with want to focus on primary care. But they shift to more lucrative medical specialties when the reality of medical school debt hits them.

Arora said a "dysfunctional" system that pays doctors for ordering tests and procedures but doesn't place a high value on prevention also deters many from choosing primary care.

Accountable care organizations to be set up under the new law aim to address some of those concerns. They would create networks of doctors, hospitals and other healthcare providers to coordinate care and keep patients healthier, eliminate needless tests, prevent errors and reduce costs.

Prospects for the organizations are uncertain. The initial design has been widely criticized, and many doctors argue that they should be in charge of the groups.

Fincher, the Georgia doctor, says the concept has some merit, and that "hospitals and doctors both are going to be held more accountable to do a better job." But she also worries primary care doctors like her in private practice will lose their independence under that set-up, and that reforms won't do enough to address pressures they face.

"When I came out of training in 1988, the promise was that it was the time of managed care and HMOs and primary care doctors were going to drive the boat," Fincher said. "They were going to be the gatekeepers. They were going to be appropriately or more handsomely reimbursed."

But within the last 10 years, doctor reimbursements with private insurers have become closely aligned with Medicare rates "and it's not paying enough," she said.

At age 51, she said, "I'm just trying to keep my practice viable and try to keep all my options open for as long as possible."