State medical boards have failed to discipline 55 percent of the nation’s doctors who were sanctioned by the hospitals where they worked, according to a report released Tuesday by Public Citizen.

The consumer advocacy group analyzed data in a federal clearinghouse from 1990 to 2009 for disciplinary action and medical malpractice payments against doctors.

Of 10,672 physicians listed in the National Practitioner Data Bank, about 55 percent, or 5,887 doctors, had been disciplined by hospitals but escaped any licensing action by the state during the entire 20-year period. The hospital discipline was to restrict or revoke the physicians’ clinical privileges.

Among the most serious violations, which involved 2,071 of the 5,887 physicians who were not disciplined, were doctors who posed an immediate threat to health or safety, were incompetent or negligent, or provided substandard care, the study found.

Other categories that triggered hospital action serious enough to be reported to the federal data bank included sexual misconduct, fraud and narcotics violations. Less serious disciplinary violations included alcohol or other substance abuse, and practicing beyond the scope of privileges.

In the District, 42 physicians were seriously disciplined by hospitals during the 20-year period, but nearly 60 percent, or 25, had no subsequent disciplinary action by the District Board of Medicine, the report found.

In Maryland, 238 physicians had their clinical privileges restricted or revoked, but the Maryland Board of Physicians failed to discipline nearly 43 percent of them, or 102 physicians.

In Virginia, 253 physicians were seriously disciplined by hospitals, but the Virginia Board of Medicine failed to sanction nearly 45 percent of them, or 113 doctors.

The report did not provide state breakdowns for the types of violations that resulted in hospital action, said Sidney Wolfe, director of Public Citizen’s Health Research Group and overseer of the study.

Officials of Washington area state boards said it was difficult to comment without knowing the specifics of the hospital discipline.

Janis Orlowski, chairman of the District Board of Medicine, said all hospitals are required to report malpractice suits against physicians to the federal database, but those cases do not necessarily result in board sanctions unless they involve care or a pattern of malpractice.

The board’s oversight of city doctors was part of a 2005 Washington Post investigation that found the medical board rarely disciplined troubled doctors. After the city beefed up the staff that investigates complaints, the District board has become one of the most improved in disciplining its doctors, according to Public Citizen.

William Harp, executive director of Virginia’s Board of Medicine, said it was possible that Virginia hospitals would discipline doctors for something that would not rise to a violation of law that would then require state board action. A doctor sanctioned by a hospital for giving substandard care, for example, would not be disciplined unless that care was proven to be negligent, he said.

A spokeswoman for the Maryland board said the top two officials were not available for comment because they were testifying at hearings in Annapolis.

Wolfe said the bottom line is that hospitals do not take actions against their physicians lightly. When they do, those actions are serious and merit oversight by state medical boards, which have the authority to oversee and revoke a physician’s license. Either state medical boards are receiving the information from the hospitals and not acting on it, or they are not receiving the information from the hospitals, he said.

“Either is alarming,” he said in a statement.

Wolfe said he is urging U.S. Health and Human Services Secretary Kathleen Sebelius to have the agency inspector general’s office reinstitute investigations of state medical boards.