Framingham Risk Calculator
Using Canadian Lipid Guidelines

ASA Derivation Tables

ASA recommendations are valid only for men using the older Framingham tables. The U.S. Preventive Services Task Force (USPSTF) recommendations take into account the risk for GI bleeding when making recommendations for men. For women, 10-year stroke risk scores are used by the USPSTF, which include history of coronary disease, atrial fibrillation and LVH. The score for women actually includes secondary prevention and requires a different algorithm for calculation. In addition, there are Framingham 10-year scores for stroke and 5-year scores for atrial fibrillation, making the choice of a risk strategy a major challenge. Thus, using USPSTF data, no recommendation can be made for women on the basis of Framingham cardiovascular risk score alone. Women over 65 seem to have the same response to ASA in prevention of MI and cardiovascular death as do men (8). From age 55 to 65, however, stroke is the main cardiovascular event, as was shown in the Women’s Health Study (8), and there are insufficient numbers of other cardiovascular events to use the older Framingham tables.

Women under age 55 are not candidates for ASA because of the infrequency of stroke at this age. There is no useful data for women over 80. Women 55-79 years with higher Framingham risk scores, who may also have coronary heart disease, atrial fibrillation or LVH, may be candidates for ASA if a stroke risk calculation is not available, but some of this intervention is secondary, and many of these patients are candidates for warfarin.

This calculator will not flag patients outside the age range likely to benefit from ASA. Men will receive a “Yes” recommendation if benefit exceeds risk of GI bleeding as outlined in the following tables from the USPSTF. Because the new Framingham tables include all cardiovascular disease (including stroke) and because other meta-analyses tend to show no difference in men and women in response to ASA (9), this calculator will flag women over age 55 with risk scores similar to men as requiring consideration for ASA. There will be more confidence in the recommendation for men and older women. All patients will require individual consideration of benefit and risk.

Diabetics may require separate consideration. They seem to have abnormal platelet function and turnover, and appear to be resistant to the beneficial effects of ASA. It is possible that they would experience the risks of ASA therapy without the benefits (10,11,12). This is not reflected in the guidelines at present.

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Population	Men Age 45-79 Years	Women Age 55-79 Years	Men Age <45 Years	Women Age <55 Years	Men & Women Age ≥80 Years
Recommendation	Encourage aspirin use when potential CVD benefit (MIs prevented) outweighs potential harm of GI hemorrhage.	Encourage aspirin use when potential CVD benefit (strokes prevented) outweighs potential harm of GI hemorrhage.	Do not encourage aspirin use for MI prevention.	Do not encourage aspirin use for stroke prevention.	No Recommendation
	Grade: A		Grade: D		Grade: I (Insufficient Evidence)

How to Use This Recommendation

Shared decision making is strongly encouraged with individuals whose risk is close to (either above or below) the estimates of 10-year risk levels indicated below. As the potential CVD benefit increases above harms, the recommendation to take aspirin should become stronger.

To determine whether the potential benefit of MIs prevented (men) and strokes prevented (women) outweighs the potential harm of increased GI hemorrhage, both 10-year CVD risk and age must be considered.

Risk level at which CVD events prevented (benefit) exceeds GI harms

Men		Women
10-year CHD risk		10-year stroke risk
Age 45-59 years	≥4%	Age 55-59 years	≥3%
Age 60-69 years	≥9%	Age 60-69 years	≥8%
Age 70-79 years	≥12%	Age 70-79 years	≥11%

The table above applies to adults who are not taking NSAIDs and who do not have upper GI pain or a history of GI ulcers.

NSAID use and history of GI ulcers raise the risk of serious GI bleeding considerably and should be considered in determining the balance of benefits and harms. NSAID use combined with aspirin use approximately quadruples the risk of serious GI bleeding compared to the risk with aspirin use alone. The rate of serious bleeding in aspirin users is approximately 2-3 times higher in patients with a history of GI ulcers.