A clinical decision support tool is an interactive software application designed to assist patients and their health professionals with decision making tasks. This clinical decision support tool for the Primary Prevention of Cardiovascular Disease provides an individualized estimate of a person's chance of having a cardiovascular event (developing coronary heart disease or having a stroke) over a ten year period of time. It also provides recommendations to reduce your risk of having a cardiovascular event based on current Canadian guidelines for the Primary Prevention of Cardiovascular Disease. And finally, it provides an estimate of the potential benefits of various risk reduction interventions (medications and lifestyle changes). It is only valid for people who have never had a cardiovascular event.

This tool is designed for adults aged 35 to 75 years who do not have heart disease, stroke, or diabetes. It is designed to help patients and their doctors decide what strategy of reducing their risk of having a heart attack or stroke is best for them.

Step 1: Enter your risk factors

To start using this tool, you must provide YOUR CURRENT RISK FACTORS:

• Your age;
• Your sex;
• Whether you currently smoke;
• Whether a closely related family member developed early coronary heart disease (before 65 years of age in a female relative or before 55 years in a male relative);
• Your systolic blood pressure (systolic blood pressure is the first number of your blood pressure reading. For example, if your reading is 120/80 (120 over 80), your systolic blood pressure is 120);
• Whether you are currently taking medication to lower your blood pressure;
• Your total cholesterol in mmol/L;
• Your HDL (high density lipoprotein) cholesterol in mmol/L; and
• Your LDL (low density lipoprotein) cholesterol in mmol/L;

Step 2: Determine your current risk

YOUR CURRENT RISK ESTIMATE displays your risk of developing coronary heart disease and stroke over the next 10 years both numerically and graphically (outcomes for 100 people with your same risk factors are displayed, as this format seems to be one of the better ways to visually present risks; refer to the legend for help interpreting the graph). Risk estimates are rounded to two significant digits, although there is likely an error associated with these estimates of at least +/- 5-10%.

Step 3: Review the guideline recommendations

Individualized RECOMMENDATIONS from current Canadian guidelines for the primary prevention of cardiovascular disease based on your particular risk factors are provided. These recommendations include suggestions for lifestyle interventions as well as possible suggestions for medications.

Step 4: Explore ways to modify your risk

Select an intervention from the list of INTERVENTIONS TO MODIFY TOUR RISK. YOUR MODIFIED RISK ESTIMATE will then be displayed. Compare this new 10-year risk estimate to YOUR CURRENT RISK ESTIMATE to see how the selected intervention might benefit you in terms of reducing your risk. Risk reduction estimates are also displayed in terms of "Numbers Needed to Treat", that is, how many people would need to be treated for ten years for one person to benefit in terms of prevented coronary heart disease or stroke.

Checking the box for 'Show uncertainty (95% confidence intervals) of risk reduction data' will change both the numerical modified risk estimates and the graphical representation to display the 95% confidence interval of the clinical trial data.

Checking the box for 'Display risk of adverse events' will display the clinical trial data for adverse events related to the selected intervention.

Note that most clinical trial data comes from trial lasting less than ten years, so some caution should be exercised in interpreting these estimates.

YOUR CURRENT RISK ESTIMATE is derived using an algorithm from the Framingham Heart Study that is modified for family history using data from the Framingham Offspring Study. Clicking on the reference [6] (either here or in the calculator) will display a summary of these studies as well the literature references for them. YOUR MODIFIED RISK ESTIMATE is derived is derived by applying relative risk reduction outcomes from clinical trials to your initial risk estimate. Clinic trial data is mainly taken from systematic reviews. Clicking on the reference [7] (in the calculator) will display a summary of the applicable evidence as well the literature reference for it.

The RECOMMENDATIONS are a summary of the recommendations from 5 separate current Canadian guidelines for the primary prevention of cardiovascular disease. Clicking on the references [1], [2], [3], [4], or [5] (either here or in the calculator) will display the applicable guideline as well as the literature reference for it.

Note that the guidelines are not always in agreement on whether a particular risk reduction intervention is recommended.