Based on 2003 mortality data, 1 in 3 women are at risk for cardiovascular disease (CVD); this translates into more lives claimed by CVD than the next 5 leading causes of death combined. Currently, the best tool available for estimating a woman's risk factor is the Framingham risk score, yet most women under 70 years of age are classified as low risk using this method. These observations have prompted clinicians to incorporate other factors, such as family history and obesity (not considered in the Framingham risk score), to predict overall risk. Additionally, there has been recent interest in identifying novel risk markers that improve traditional risk factor assessment in a cost effective way.

Exercise testing can improve risk reduction in asymptomatic women

Physical fitness has long been known to reduce all-cause mortality from a plethora of diseases, most notably CVD and cancer. Investigators sought to determine if fitness tests could predict heart disease in asymptomatic women. In a study of 2,994 North American asymptomatic women aged 30 to 80, exercise capacity and heart rate recovery (HRR) was tested and correlated with cardiovascular and all-cause mortality (Mora S. JAMA 2003; 290:1600). After age-adjustment, women who were below the mean for exercise capacity and HRR had a 3.5-fold increased risk of cardiovascular death compared to women who had above average values for both tests. This large increase in risk justifies the use of exercise testing and HRR in predicting CVD in asymptomatic women, combined with traditional risk factors.

Other non-traditional markers improve risk prediction in women

Recent data has suggested that plaque burden can be predictive of CAD risk. In a cohort of 10,377 asymptomatic women, calcium scores >1000 were 4.03 times more likely to experience CVD-related death as women whose calcium scores were <10 (Shaw LJ. Radiology 2003; 228:826). Additional factors demonstrating promising correlations with increased risk of CV events are levels of the inflammatory marker C-reactive protein, the ankle brachial index (measurements of blood pressure in the ankle and the arm) and carotid-artery media and intima thickness. The ongoing MESA trial (Multi-Ethnic Study of Atherosclerosis), involving over 6,000 men and women between the ages of 45 and 84, will likely help us better understand the importance of sub-clinical disease measures in preventing CVD events, especially in women.

Cost considerations in CVD screening

The cost of CVD and stroke in the United States in 2006 is projected to be $403.1 billion including direct and indirect costs, according to the Centers for Disease Control and Prevention. The use of screening tests to decrease this economic burden is therefore attractive, as long as the screening strategies succeed. Possible reasons why a screening strategy might fail are: clinicians do not act on screening results, available therapy may be ineffective, or real-world application of therapy may not yield expected results. Conversely, there is also the possibility that screening strategies may themselves improve adherence to clinical guidelines, observes Vera Bittner, MD, Professor of Medicine from the University of Alabama in Birmingham. Currently, however, there is insufficient data on the benefits of screening methods for CVD. In the future, studies must correlate screening tests not only to increases in risk, but to actual health benefits.