ASCVD 10-Year Risk Calculator

Background.

Out of 100 people with your age, cholesterol, blood pressure, smoking and diabetes status, how many would have a first heart attack or stroke in the next ten years? That is the question the Pooled Cohort Equations answer. They were published in the 2013 ACC/AHA Guideline on the Assessment of Cardiovascular Risk and became a widely used way for clinicians to put a number on cardiovascular risk before deciding how hard to push prevention, including whether to discuss a statin.

The event being predicted is a first hard atherosclerotic cardiovascular disease (ASCVD) event: a nonfatal heart attack, death from coronary heart disease, or a stroke, fatal or not. The equations were fitted to pooled data from several long-running US cohort studies, among them ARIC, the Cardiovascular Health Study, CARDIA and the Framingham original and offspring cohorts. Those cohorts had enough long-term follow-up to produce separate equations for only four groups: non-Hispanic White women, White men, African-American women and African-American men, aged 40 to 79 and free of known cardiovascular disease.

Those limits are built in. Age is accepted only from 40 to 79, and race only as White or African-American, because no published coefficients exist outside them. The guideline does say, as expert opinion rather than validated evidence, that the White equations may be considered for people of other backgrounds, so anyone choosing that option should know the estimate may be too high or too low for them.

The result is a percentage, labelled low below 7.5% and elevated at 7.5% or above. That single cut-point is the one the 2013 guidelines used to mark where a more active conversation about lowering risk begins. It is an estimate for people who look like you on paper, not a prediction for you, and it does not replace a clinician's assessment, which will take in family history, other conditions and your own preferences. People who have already had a heart attack or stroke are outside the equations altogether.

What is ascvd risk calculator?

A 10-year ASCVD risk is the estimated probability that a person with no known cardiovascular disease will have a first hard ASCVD event within ten years. The Pooled Cohort Equations produce it from a proportional-hazards survival model: a weighted sum of the logarithms of age, total cholesterol, HDL cholesterol and systolic blood pressure, some multiplied by log age, plus terms for current smoking and diabetes. Each sex and race group has its own weights, its own average sum and its own baseline 10-year survival, so the same measurements give different answers in different groups.

How to use this calculator.

1. 01Enter age in whole years between 40 and 79, then choose sex and race. Race is limited to White or African-American, the two groups with published equations.
2. 02Enter total and HDL cholesterol in mg/dL from a recent lipid panel. If your report is in mmol/L, multiply by 38.67: 5.5 mmol/L total cholesterol is about 213 mg/dL.
3. 03Enter systolic blood pressure, the upper number, in mmHg. An average of several readings is more representative than a single measurement taken in a hurry.
4. 04Answer yes to blood pressure medication if you currently take any drug to lower blood pressure, even if your readings are now normal. Then answer the smoking and diabetes questions.
5. 05Read the 10-year percentage and its category, and take both to your clinician, who can weigh factors the equations leave out.

The formula.

Risk = 1 − S₀(10)^exp(Σ − mean). Σ is the individual sum: each risk factor is transformed, multiplied by its group's coefficient from Appendix 4, Table A of the 2013 guideline, and added up. Age, total cholesterol, HDL and systolic pressure enter as natural logarithms. Some groups also use products such as ln(age) × ln(total cholesterol), which let the effect of cholesterol weaken or strengthen with age, and a squared log-age term appears only in the White women's equation. Smoking and diabetes enter as 0 or 1.

Systolic pressure has two coefficients in every group, one for treated and one for untreated pressure, and only the one matching your answer is used. Each group has a mean sum, the average Σ in its derivation sample, and a baseline survival S₀(10), the share of a person with exactly average risk factors who stayed event-free for ten years: 0.9665 for White women, 0.9533 for African-American women, 0.9144 for White men and 0.8954 for African-American men.

exp(Σ − mean) is a hazard ratio: above 1 if your risk factors are worse than the group average, below 1 if better. Raising S₀(10) to that power gives your own 10-year event-free probability, and subtracting it from 1 gives the risk. The result always lies between 0% and 100%. When the guideline applied the equations to a national survey sample it truncated estimates at 1% and 30% because they become unstable near the edges of the data, so very low and very high results deserve extra caution.

A worked example.

Frequently asked questions.

References& sources.

1. [1]Goff DC Jr, Lloyd-Jones DM, Bennett G, Coady S, D'Agostino RB Sr, Gibbons R, Greenland P, Lackland DT, Levy D, O'Donnell CJ, Robinson J, Schwartz JS, Shero ST, Smith SC Jr, Sorlie P, Stone NJ, Wilson PW. 2013 ACC/AHA Guideline on the Assessment of Cardiovascular Risk. Circulation, published online November 12, 2013. Appendix 4, Table A and Table B — the source of every coefficient used in this calculator.
2. [2]American College of Cardiology. CVD Risk Estimator Plus. Official ACC/AHA-hosted implementation of the 2013 Pooled Cohort Equations (and the newer PREVENT equations).
3. [3]Goff DC Jr, et al. 2013 ACC/AHA guideline on the assessment of cardiovascular risk: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. Circulation. 2014;129(25 Suppl 2):S49-73. PubMed record.