Male and Female Physicians Refer Women for Cardiac Diagnostic Procedure Less Often than Men, Yale Researchers Report

In the first large national study on the topic, Yale researchers found male and female physicians were more likely to refer men than women for cardiac catheterization, a diagnostic procedure used to assess blood flow to the heart, after a heart attack.

The study suggests that the higher rates of cardiac catheterization among men do not only reflect the sexist prejudices of male doctors toward female patients. Whatever factors influence this pattern of care appear to involve both male and female physicians.

Published in the December 12 issue of the Journal of the American Medical Association, the study showed that elderly women were 10 percent less likely to undergo cardiac catheterization after a heart attack than men, even after accounting for clinical differences between men and women.

“These data provide strong evidence that women and men are treated differently after they have had a heart attack,” said senior author Harlan Krumholz, M.D., associate professor of medicine at Yale School of Medicine, and director of the Yale-New Haven Hospital Center for Outcomes Research and Evaluation.

The issue of disparities in health care and outcomes has received significant attention. However, Krumholz noted that most investigators have focused on documenting differences in care by sex, but this investigation extends previous work by examining the influence of gender differences among physicians on choices in care.

“Concerns that gender differences in procedure use primarily reflect the behavior of male physicians are not supported by these findings,” said the study’s first author Saif Rathore, research fellow in the Department of Internal Medicine at Yale. “Gender differences in cardiac catheterization rates were also present among patients who received care from female physicians.”

Using data from the Cooperative Cardiovascular Project, a federal initiative to improve the care of Medicare patients hospitalized for acute myocardial infarction in 1994 and 1995, the team evaluated whether differences between men and women in the use of cardiac catheterization varied according to the gender of their attending physician.

They found that of 49,583 men and 54,648 women with acute myocardial infarction, physicians of both genders referred women for cardiac catheterization about 10 percent less often than men. The authors note that while the study cannot preclude the existence of sexual discrimination or prejudice, “it does suggest that if physician factors contribute to gender differences in cardiac catheterization use, be it by perceptions of heart disease in women or other attitudes, then these factors are apparently common to both male physicians and female physicians,” noted co-author Jersey Chen, resident in the department of radiology at the University of Pennsylvania.

Krumholz said the findings underscore the complexity of this issue. “We did find a difference in the rates of cardiac catheterization that could not be explained by gender differences in the clinical characteristics of the patients, their physicians or the type of hospitals where they received treatment. We could not illuminate the reason for these differences.”

The authors also found that patients treated by male physicians were six percent more likely to undergo cardiac catheterization than patients treated by female physicians. “It is unclear what factors may result in male physicians referring more of their patients for cardiac catheterization than female physicians, but data concerning other medical tests have shown that male physicians and female physicians can refer patients at different rates,” noted Rathore. “Clearly, additional research is needed to confirm this finding,” he said.

Study authors include Krumholz, Rathore, Chen, Martha Radford, associate professor of medicine at Yale; Yongfei Wang, statistical analyst; and Viola Vaccarino, M.D., researcher at Emory University School of Medicine.