Baltimore-area doctors earn on average some of the lowest salaries in the country despite the city being home to one of the world’s most well-respected medical institutions, according to a new survey by Doximity, a social network for health care professionals.

The compensation report found that on average the region’s physicians earned $281,005 a year. In only two other metropolitan areas did doctors report lower salaries. The average salary was $267,598 in the areas of Durham, N.C., and $272,398 in Ann Arbor, Mich., and surrounding areas.

The highest-paid physicians in the country live in the Charlotte, N.C., area and make on average $359,455 a year.

The report didn’t look at why the salaries differed by region. The number of academic hospitals, including Johns Hopkins Hospital, which tend to pay less, could have something do with the lower salaries in the Baltimore market, suggested study co-author Joel Davis, vice president of strategic analytics at Doximity.

The region’s supply of doctors is also plentiful, so salaries might not be as competitive, Davis said. Rural and lower-cost cities tend to pay better because they probably needed to compensate more to attract doctors, Davis said.

The Baltimore region was also among five that paid the lowest average salaries to female physicians, who made $226,048 on average. But the area also had one of the smallest gender wage gaps in the country: Male doctors made 24 percent more than female doctors.

The smallest wage gap was in Sacramento, Calif., where male doctors make 19 percent more than their female colleagues. The report said that difference is about what it would take to pay the salaries of two medical assistants in the Sacramento area.

Researchers are not sure why the wage gap exists, Davis said.

“We think just by bringing transparency to the wage gap it could prompt some other researchers to look more into it,” Davis said.

—Andrea K. McDaniels