Nearly 6,000 doctors along the Gulf Coast were uprooted by Hurricane Katrina in the largest displacement of physicians in U.S. history, university researchers reported Monday.

How many of those doctors will set up shop permanently in other cities, or decide to retire instead of reopening their practices, remains as unclear as New Orleans's future.

"We don't know what this is going to mean to health care," said Thomas Ricketts, who led the study by researchers at the University of North Carolina at Chapel Hill. "We've never had to deal with something like this before."

Ricketts's study found that 5,944 doctors were displaced in the 10 counties and parishes in Louisiana and Mississippi that were directly affected by Katrina-related flooding. That number covers doctors caring for patients, not those who are administrators or researchers, said Ricketts, a professor of health policy and administration at UNC's School of Public Health.

The finding is based on an analysis of American Medical Association data, information posted by the Federal Emergency Management Agency and other records.

More than three-quarters of the doctors displaced came from the New Orleans parishes of Orleans, Jefferson and St. Bernard.

More than half were specialists, with 1,292 in primary care and 272 in obstetrics and gynecology, the study said.