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Heart Bias Study Was Misinterpreted - Sunday, August 15, 1999
BOSTON (AP) -- The editors of the New England Journal of Medicine say they "take responsibility" for media reports which greatly exaggerated conclusions in a study about possible gender and sex bias in heart care. The study, published in the Journal on Feb. 25, reported what happened when doctors viewed taped interviews of actors describing their identical symptoms and were asked what treatment they would recommend. It found that, in cases of equally sick patients, doctors were less likely to refer blacks and women than they were whites and men to have cardiac catheterization, a test used to diagnose heart disease. Several news organizations, including the AP, interpreted the study to show that doctors were 40 percent less likely to order the tests for women and blacks than for men and whites. However, a followup published in the Journal recently concluded that the likelihood of women and blacks being referred for the tests was actually 7 percent less than for men and whites. The followup, written by Dr. Lisa M. Schwartz and others from the VA Outcomes Group in White River Junction, Vt., said the misunderstanding resulted from the original study's use of an "odds ratio" to report the differences rather than a more commonly used "risk ratio." The researchers calculated the odds in favor of blacks being offered the test and of whites being offered the test. Then they calculated the ratio of these two figures. The ratio of blacks' odds to whites' odds worked out to 0.6, as did the ratio of women's odds to men's. The media interpreted this to mean that women and blacks were 40 percent less likely to be offered catheterization. But the true difference is much smaller. A table published with the study shows that actually 85 percent of women and blacks were referred for catheterization as were 91 percent of men and whites. This means that the risk ratio was .93. In other words, the probability of referral was 7 percent lower for blacks and women than for whites and men. The journal editors said they "take responsibility for the media's overinterpretation" of the study's findings and said they should not have allowed the use of odds ratios in the study's summary. http://www.usatoday.womenconnect.com/LocLink/MEDC/HEART

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