ORLANDO, FLA. -- Duke University Medical Center researchers have found an interesting paradox about gender differences in heart disease -- women have a greater burden of hypertension than their male counterparts and they receive more aggressive treatment for it, yet they obtain no better blood pressure control.
Since their study also found that the impact of hypertension on mortality or recurrent cardiac events was similar between men and women, the researchers believe there are great opportunities to improve medical therapy and outcomes in women.
Cardiologist Kristin Newby, M.D., of the Duke Clinical Research Institute, presented the results of her analysis today (Nov. 12, 2003) at the 76th annual scientific session of the American Heart Association.
Newby wanted to know how the prevalence and treatment of hypertension varied between the sexes in patients who came to the hospital with an acute coronary syndrome (ACS), which occurs when a patient arrives at the hospital with chest pain and physicians must determine whether or not the symptoms are due to unstable angina or signal a real heart attack.
"Hypertension afflicts more than one billion worldwide and has been proven to be an independent risk factor for death or further cardiac events after ACS," Newby explained. "There is little doubt that hypertensive women with ACS are at a higher unadjusted risk for death or heart attack, but when you statistically adjust for such factors as age, kidney function, diabetes or other heart problems, the risks turn out to be about the same. The difference in outcomes does not appear to be due totally to gender, but at least in part to these and other factors."
To answer that question, Newby consulted data gathered from two related international trials -- SYMPHONY and 2nd SYMPHONY (Sibrafabin vs. aspirin to yield maximum protection from ischemic heart events post-acute coronary syndromes). While these trials were designed to compare the effectiveness of aspirin to a new class of drugs that dissolves blood clots, researchers at the 931 participating centers also collected data on each patient's medication history and outcomes.
Newby's analysis included 2,091 women and 5,084 men enrolled in the SYMPHONY trials in the US. She found that 63 percent of women had hypertension, compared to 50 percent of the men. The women with hypertension tended to be older, had reduced kidney function and more often had diabetes and a history of heart failure when compared to men. However, they had fewer previous heart attacks or invasive procedures to improve blood flow to the heart.
"What we found so interesting was that women received more and different agents to reduce blood pressure than did the men," Newby said. "What is confusing is that this difference in the number of drugs to control hypertension still did not have any significant effect, when compared to the men."
Specifically, 16 percent of the women were prescribed three different drugs to control hypertension, compared to 13 percent for men. Almost 35 percent of women received two different drugs, compared to 30 percent for men. The classes of drugs used most often to control blood pressure were ACE inhibitors, beta-blockers, calcium channel blockers and diuretics.
"While women were more likely to get multi-drug treatments, they still had higher blood pressures," Newby continued, adding that systolic pressure was 150 millimeters of mercury (mmHg) at presentation in women and 147 mmHg in men. Even after treatment for the acute coronary syndrome, blood pressure remained higher in women (126 mmHg vs. 124 mmHg in men). "Thus, it is not clear if women are not getting the right medicines, are getting them in the wrong doses, or if other factors are responsible for the need for more medications in women to attain similar control."
After considering other factors that affect prescribing, the only anti-hypertensive drugs women received significantly more often than men were a class of drugs known as diuretics. Newby cannot explain why 32.7 percent of the women received a diuretic, compared to only 19.3 percent for men.
Newby said that physicians need to be aggressive in treating hypertension, whether their patients are male or female. She added that awareness of the disease -- both on the part of physicians and patients -- is important to reducing the prevalence of hypertension and therefore reduce the risk for heart attacks.
"Hypertension is often forgotten about, a silent disease," she said. "Awareness may be the key, since the disease itself does not make patients feel bad. A lack of awareness affects compliance with medications, going to the doctor for check-ups, eating healthful meals -- all those things that are helpful in keeping hypertension in control."
Both of the SYMPHONY trials were funded by F. Hoffmann-La Roche, Basel, Switzerland. Newby's analysis was funded by Novartis, Basel, Switzerland.