Women with heart problems may be “tougher” about their disease than their male counterparts, a new University of Michigan study suggests. And that difference may help explain why they’re less likely to get aggressive care for the No. 1 killer of both women and men.

In a study published in the most recent issue of the American Journal of Medicine, researchers from the U-M College of Pharmacy and the U-M Cardiovascular Center report the results of an exhaustive survey of 490 heart patients treated at U-M for a heart attack or severe chest pain who were enrolled in a research registry.

In all, the 142 women and 348 men rated the severity of their heart disease about the same. But in fact, the women had much worse disease, took many more medicines, and experienced more serious symptoms and limitations on their daily lives, according to their medical records and answers on standardized questionnaires.

In other words, the women who had major problems related to their heart disease were just as likely to rate their disease as “mild to moderate” as men with far less-severe problems. And when the researchers took into account the differences between patients, the men were significantly more likely than women with similar disease levels to perceive their disease as severe.

“It’s important to understand women’s perceptions, beliefs and attitudes about cardiac disease and its treatment,” says senior author Steven Erickson, Pharm.D., an associate professor of clinical sciences in the College of Pharmacy and a clinical pharmacist at the U-M Health System. “If women do not perceive their cardiac disease as severe, they may not pursue medical evaluation, treatment or rehabilitation.”

Indeed, previous studies by other researchers have shown that women heart-attack survivors, for example, are less likely to go for post-heart attack rehab programs involving exercise and education to help patients improve their health. Women are also more likely to delay seeking help for heart-related symptoms than men, and are less likely to receive heart-related diagnostic and therapeutic procedures.

The root cause of these gender differences has puzzled researchers for years, says co-author Kim A. Eagle, M.D., FACC, clinical director of the U-M CVC and the Hewlett Professor of Internal Medicine at the U-M Medical School.

“Physician bias and lack of awareness have been leading suspects, but no one has examined differences in attitudes,” he says. “Although our study cannot prove that women’s ‘toughness’ influences their tendency to seek and accept aggressive care for their heart problems, we hope it prompts further investigation of this question.”

The study, published in the November issue of AJM, is based on data from the U-M CVC’s Acute Coronary Syndrome/Myocardial Infarction Patient Registry, which includes thousands of U-M heart attack and angina patients.

The patients surveyed for the study had been admitted to the hospital for a heart attack or chest pain episode between July 1999 and November 2002, and were surveyed in 2003.

The patients provided demographic data about themselves, reported how many medications they were taking, and completed standardized questionnaires that assessed the severity and impact of their heart-related symptoms and other medical conditions, any limits on their physical function and activity, and their heart’s capacity to help them perform daily activities and exercise.

The questionnaire also included the question “How severe do you think your heart disease is?” and asked patients to select from five choices: very mild, mild, moderate, severe and very severe. For the paper, patients were grouped into two groups: very mild/mild, and moderate/severe/very severe.

The researchers performed basic statistical analyses on the patients’ responses that examined the relationships between aspects of patients’ health status and perceived heart disease severity. They also performed multivariate analysis that controlled for actual disease severity and patient characteristics while analyzing the relationship between gender and perceived disease severity.

In all, the groups of women and men in the study had about the same distribution of age, race, type of heart problem, time since most recent cardiac event and number of co-existing diseases. On the whole, the women had lower heart capacity for daily activities, lower health-related quality of life, and lower physical, mental and general health status than men.

Nevertheless, 42 percent of the women rated their heart disease as very mild or mild — no different from the 40.9 percent of men who gave the same rating.

When the researchers performed the more sophisticated statistical analysis, they found that women indeed showed signs of being “tougher” about their heart diseases. Even after all differences in patients, their diseases and their treatments were controlled for, men were far more likely to perceive their heart disease as severe.

Erickson, Eagle and their co-authors note that their study does not take into account functional problems related to other health issues that patients might have had before their heart attack or angina. They also say that previous research has suggested that women in general are more affected physically, mentally and socially by heart disease than are men; this new study cannot address that potential difference.

But, they say, their data suggest that there’s a relationship between gender and perception of disease severity – a relationship that might help explain the “gender gap” in delivery of heart-related health care to those who have survived a heart attack or bout of angina.