Significant improvements have been made in some hospitals since the Institute of Medicine released a landmark report in 2000 that revealed many thousands of Americans die each year because of medical mistakes.

But nationwide, the pace of change is painstakingly slow, and the death rate has not changed much, according to the study in The Journal of the American Medical Association.

The researchers blame the complexity of health care systems, a lack of leadership, the reluctance of doctors to admit errors and an insurance reimbursement system that rewards errors — hospitals can bill for additional services needed when patients are injured by mistakes — but often will not pay for practices that reduce those errors.

"The medical community now knows what it needs to do to deal with the problem. It just has to overcome the barriers to doing it," says study co-author Lucian Leape of Harvard's School of Public Health.

The institute, a public policy organization, pushed key health care organizations to focus on patient safety, the new report says. As a result, reductions as much as 93% have been made in certain kinds of error-related illnesses and deaths.

Computerized prescriptions, adding a pharmacist to medical teams and team training in the delivery of babies are among the improvements medical centers are making, the study finds.

But "we have to turn the heat up on the hospitals," Leape says.

For example, 5% to 8% of intensive-care patients on ventilators develop pneumonia, the study says. But by strictly following a simple protocol of bed elevation, drugs and periodic breathing breaks, those outbreaks can be reduced to almost zero. "A little hospital in DeSoto, Miss., called Baptist Memorial did it, so it doesn't take a big academic medical center," Leape says.

Hospitals that eliminate infections should receive bonuses, Leape says. "If insurance companies paid 20% more for patients in (intensive-care units) where there were no infections, they'd cut costs substantially.

"We really need to rethink how we pay for health care. What we do now is pay for services, but what we should do is pay for care and outcomes."