Background: The 2007 update to the American Heart Association (AHA) guidelines for cardiovascular disease prevention in women recommend a simplified approach to risk stratification. We assigned Women's Health Initiative participants to risk categories as described in the guideline and evaluated clinical event rates within and between strata.
Methods and results: The Women's Health Initiative enrolled 161 808 women ages 50 to 79 years and followed them prospectively for 7.8 years (mean). Applying the 2007 AHA guideline categories, 11% of women were high risk, 72% at-risk, and 4% at optimal risk; 13% of women did not fall into any category, that is, lacked risk factors but did not adhere to a healthy lifestyle (moderate intensity exercise for 30 minute most days and <7% of calories from saturated fat). Among high risk, at-risk, and optimal risk women, rates of myocardial infarction/coronary death were 12.5%, 3.1%, and 1.1% per 10 years (P for trend <0.0001); the event rate was 1.3% among women who could not be categorized. We observed a graded relationship between risk category and cardiovascular event rates for white, black, Hispanic, and Asian women, although event rates differed among ethnic groups (P for interaction=0.002). The AHA guideline predicted coronary events with accuracy similar to current Framingham risk categories (area under receiver operating characteristic curve for Framingham risk, 0.665; for AHA risk, 0.664; P=0.94) but less well than proposed Framingham 10-year risk categories of <5%, 5% to 20%, and >20% (area under receiver operating characteristic curve for Framingham risk, 0.724; for AHA risk, 0.664; P<0.0001).
Conclusions: Risk stratification as proposed in the 2007 AHA guideline is simple, accessible to patients and providers, and identifies cardiovascular risk with accuracy similar to that of the current Framingham algorithm. Clinical Trial Registration- clinicaltrials.gov. Identifier: NCT00000611.