Study authors say their work offers the first empirical evidence for what many have long suspected: that coverage limitations imposed by managed care are infiltrating doctor-patient communications.
"Patients aren't getting the whole story," said Matthew K. Wynia, director of the Institute for Ethics at the American Medical Association and lead author of the article being published in the journal Health Affairs.
"Almost a third of physicians reported sometimes not offering useful services to patients because of health plan coverage restrictions," he told CBS Radio News.
Wynia and his colleagues, independent of the AMA, surveyed 700 physicians in the U.S. in 1998 and 1999, and asked how often they had decided not to offer a "useful service to a patient because of health plan rules." Forty-two percent said never, and 27 percent said rarely.
But 23 percent said "sometimes," and 8 percent said "often" or "very often."
"My hunch is there's a beneficent sort of motivation behind this that says that physicians think why dangle a service in front of someone who's not going to be able to afford it and it's therefore not really a realistic option," Wynia said. "That, in essence, cuts the patient out of the decision making process.
The results are similar to a controversy several years ago, when some managed care companies barred doctors from discussing medical options not covered by the health plan. Public outcry persuaded most companies to drop those rules, known as "gag clauses," and many states banned them from contracts.
The study found that doctors whose own salaries are closely tied to controlling costs were more likely than other doctors to report withholding information.
In addition, those who serve a large number of Medicaid patients were more likely to stay silent.
"The presumption might be on the part of the physician that patients on Medicaid can't afford uncovered care, so they might be a little more likely to not mention uncovered services to patients," Wynia said.
Authors note an important caveat: The term "useful service" was not defined in the survey. To one doctor that could mean steering a patient to a generic drug rather than the more expensive brand-name version, while to another it could mean not mentioning a major surgical procedure.
The most positive interpretation of the study's results would be that doctors are withholding information on services that might be useful but are less clearly necessary than others, said Dr. Hoangmai Pham, senior health researcher at the Center for Studying Health System Change, who was not part of the research team.
The most negative interpretation, she said, is that doctors have been conditioned to withhold information, shortchanging patients.
All of it can be compounded by time pressures, Pham said: Doctors with a limited amount of time with a patient may not spend it talking about services that the patient has no way to pay for.
"It's simply not possible to discuss everything with every patient," she said. "You might go down your list of three or five top options but not discuss every last one."