The findings from three large, federally funded studies indicate it's possible to equalize health care between races, but it won't happen quickly or easily.
"Things that are simpler and less expensive ... are easier fixes," said Dr. Ashish Jha, of the Harvard School of Public Health. He said more progress probably won't happen "by small tinkering with the system."
He led one of the three studies published in Thursday's New England Journal of Medicine. The research offers some of the first evidence that racial disparities have narrowed, at least for some patients and treatments.
Since the 1980s, many studies have documented racial gaps in the standard of health care. They are blamed on economic, cultural and even biological differences between races. Blacks have less access to better doctors, hospitals and health plans, studies indicate.
Research also shows that the medical system treats whites and blacks differently, even when they are the same in nearly every way. Examining only those two races, the new studies took into account differences like health plans, hospitals, regions and wealth.
The researchers mostly compared treatment of whites and blacks by assessing how often accepted professional standards were met for each group. In the study finding the most equality, Harvard researchers analyzed records from 1.5 million patients in 183 Medicare managed-care plans between 1997 and 2003.
They found narrowed racial gaps for mammograms and diabetics' eye exams, blood-sugar tests, and testing and control of diabetics' cholesterol. Gaps were also reduced for prescribing beta-blocker heart drugs and cholesterol testing after heart attacks.
The most dramatic improvement came for beta blockers. By the end of the study, 93 percent of blacks met standards, compared to 94 percent of whites, an improvement of 11 percentage points for blacks.
Progress wasn't apparent everywhere, though. Racial disparities widened by three percentage points for both control of diabetics' blood sugar and of heart patients' cholesterol.
The other two studies, led by Harvard and Emory University in Atlanta, show persistent disparities in mostly expensive and elaborate procedures like some blood vessel repairs, heart and back surgeries, and joint replacements.
"The more invasive the procedure was, the more difference we found," said Dr. Viola Vaccarino, who led the Emory study.
By contrast, with a simple treatment like aspirin, blacks and whites were handled similarly.
The studies weren't designed to pinpoint the precise reasons for the gaps or changes over time. However, researchers said more elaborate treatments are harder to improve quickly because they involve multiple steps and resources. They may require coordination between doctors, hospitals, and pharmacies.
"Ordering a test is ... relatively easy, compared to controlling the level of cholesterol," said Dr. Amal Trivedi, lead researcher in the managed-care study. "With cholesterol control, it's quite costly to take regular medicine."
Alan Nelson, a retired doctor who oversaw a congressionally mandated report in 2002 on racial differences in care, agreed that more expensive care may be harder to upgrade quickly. But he said he believes that cost doesn't drive the doctors to handle patients differently.
The managed-care study also suggests that better medicine can close racial gaps, doctors said. The federal government required Medicare managed-care plans to measure and report more on their performance starting in 1997, at the beginning of the study. Care for whites also improved, though not as much as for blacks.
Doctors said treatment can be further equalized with universal insurance coverage, more data on race, more awareness of disparities, and medical improvements like linking doctor and hospital payments to performance.
"No one should fool anyone that this is going to happen overnight ... because the health system is so complex," added Dr. Georges Benjamin, director of the American Public Health Association.