Medical expenses remain out of control in the U.S., where Americans have an “unsustainable attitude” that ignores the increasing cost of health care, the chief executive officer of insurer Aetna Inc. said.

While the rise in medical costs has slowed since the last recession, the U.S. still needs to switch to a “fundamentally different” system that pays for the quality of care rather than the quantity, Mark Bertolini said in a Bloomberg Television interview from Davos, Switzerland.

“Our health-care costs are not under control right now,” Bertolini said. “We really need to look at how health care is delivered and how we pay for it. Today, we pay for each piece of work done and so we get a lot of pieces of work done.”

Spending on drugs, hospitals and other services rose 3.7 percent in 2012, half the rate from before the recession that ended in 2009. While Bertolini ascribed the slowdown to the economy, the U.S. health-care law known as Obamacare also has encouraged collaborations among doctors and hospitals to coordinate patient care. Companies including Hartford, Connecticut-based Aetna, the third-biggest U.S. insurer, have started their own “accountable care” partnerships.

Instead of a medical system of solo practitioners, U.S. health-care needs to “bring the whole team together to get the right services” to patients, Bertolini said from Davos, where he was attending the World Economic Forum.

Americans are gaining more control and more responsibility for their medical bills, Bertolini said, with individuals paying about 40 percent of costs through premiums, deductibles and other charges.

Bertolini said he has first-hand experience with a confusing U.S. health-care system he described as “a maze.” The CEO injured his spinal cord in a 2004 skiing accident and donated a kidney to his son in 2007.

“We’re heading toward a consumer market,” the CEO said. “Consumers want choice. They want it to be simple and they want it to be about them and right now, we don’t have a system that does that for them.”