About one-in-twenty women who are low-risk, according to current classification standards, may be at higher risk for heart disease if evidence is found of advanced coronary artery calcium, says an article in Archives of Internal Medicine (JAMA/Archives), December 10/24 issue.
The authors explain that the Framingham risk score is the most common approach for assessing a person’s likelihood of developing coronary heart disease during the next ten years – the assessment takes into account such factors as the patient’s age, blood pressure and cholesterol levels.
If an person in the USA has a risk of under 10% during the coming decade he/she is considered as low-risk – a high risk person would be one whose likelihood is at least 20%. About 95% of all American women under 70 are considered low-risk, and consequently do not qualify for aggressive management risk factors. “Nevertheless, most women will ultimately die of heart disease, suggesting that the Framingham risk score alone does not adequately stratify women in ways that would be useful for targeted preventive interventions,” the researchers say.
Susan G. Lakoski, M.D., M.S., Wake Forest School of Medicine, Winston-Salem, N.C., and team looked at 3,601 women, aged 45-84 in this study. The study started in 2000. CT (computed topographic) scans determined their scores for coronary artery calcium. A high score – meaning significant calcium deposits are presents – are not included in the Framingham risk score. In 2000 details on the women’s medical history, body measurements and laboratory tests were also taken. They were all interviewed by telephone every 9-12 months about any subsequent cardiovascular diagnoses or admissions to hospital.
According to the Framingham risk score, 90% (2,684) of the women were considered low-risk. However, 32% of them had detectable amounts of calcium in their coronary arteries. During the following 3.75 years (average) 24 of the low-risk individuals had heart events – a risk of 0.9% – and 34 had a cardiovascular disease event, such as a heart event, stroke or death – 1.3% risk.
“Compared with women with no detectable coronary artery calcium, low-risk women with a coronary artery calcium score greater than zero were at increased risk for coronary heart disease and cardiovascular disease events.”
Nearly 5% of the low-risk women had a score of at least 300, meaning they had advanced coronary artery calcium. They ran a 6.7% risk of a heart event, as well as an 8.6% risk of a cardiovascular event during the 3.75-year follow-up.
The researchers wrote “These data shed new light on cardiovascular disease risk and the modalities to evaluate and treat middle-aged and older women. This study also provides novel data in support of the 2007 guidelines on cardiovascular disease prevention in women, suggesting that women with coronary artery calcium are at potentially higher risk than a Framingham risk score classification would suggest.”
To determine which low-risk women should be screened for coronary artery calcium or treated more aggressively further studies are needed with longer follow-up periods, the researchers conclude.
Arch Intern Med. 2007;167(22):2437-2442
Written by – Christian Nordqvist