Algorithms

Our Calculators

Heart Attack and Stroke Calculator (Cardiovascular disease)

"What sets this cardiovascular risk calculator apart from other calculators worldwide is that it looks at healthy living, and it is better calibrated to the Canadian population," says Dr. Doug Manuel, lead author of the Cardiovascular Disease Population Risk Tool (CVDPoRT) in the Canadian Medical Association Journal.

The calculator uses responses from 104,219 Ontario residents from the Canadian Community Health Surveys (2001 to 2007) linked to hospitalizations and deaths to develop and validate CVDPoRT.

The calculator allows individuals to predict their risk of hospitalization or death from cardiovascular disease within the next five years. For example, if their risk is 5%, it means that 5 in 100 people like them will experience a serious cardiovascular event in the next five years. The calculator also provides heart age, an easy-to-understand measure of heart
health.

The Cardiovascular Disease Population Risk Tool considers many factors, including sociodemographic risks, health behaviour risks (smoking status, alcohol intake, diet and  physical activity), health conditions and more.

"People are interested in healthy living, but we don't often have that discussion in the doctor's office," says Dr. Manuel. "Doctors will check your blood pressure and cholesterol levels, but they don't necessarily ask about lifestyle factors that could put you at risk for a heart attack and stroke. We hope this tool can help people—and their care team—obtain better information about healthy living and options for reducing their risk of heart attack and stroke."

In addition to personal use, policy-makers can use the tool to calculate risk profiles for different populations. Currently set up for use in Canada, it can be adapted for any of the 100 countries around the world that collect health survey data.

Life Expectancy Calculator

The life expectancy calculator was developed using a statistical model to estimate the risk of death associated with smoking, unhealthy alcohol consumption, poor diet, and physical inactivity in Ontario. We calculated the risk of death for Ontarians who responded to Canadian Community Health Surveys from 2001 to 2008 and agreed to have their responses linked to their personal health information. There were approximately 1 million person-years of follow-up and over 9000 deaths in the development and validation datasets. The study adjusted for a wide range of risk factors, in addition to health behaviours and was published in PLoS Medicine.

The original life expectancy calculator was developed using Canadian Community Health Surveys from 2001 to 2005 (550 000 person-years of follow-up, with over 6000 deaths). For more information about the original study see www.publichealthontario.ca or www.ices.on.ca.

Stroke Calculator

The stroke calculator was created with the Stroke Population Risk Tool (SPoRT). SPoRT is a predictive risk algorithm that estimates the risk of hospitalized stroke based on healthy living and other sociodemographic and health indicators. Risk of stroke was assessed for 82 259 Ontarians who responded to Canadian Community Health Surveys from 2001 to 2005 and agreed to have their responses linked to their personal health information. People were followed for over 668 000 person years, with over 3 236 incident stroke events observed. The study adjusted for a wide range of risk factors, in addition to smoking, physical activity, diet, alcohol and stress. For more information, see the PLoS One Study here.

Health Care Cost Calculator

The health use calculator was based on the largest study to directly link healthy living and sociodemographic indicators to comprehensive health care. Health care costs for hospital, drugs, physician services and other government-funded health care were examined for 80,000 Ontarian respondents of the Canadian Community Health Survey who agreed to have their responses linked to their personal health information. In total, there was $430 billion in Ontario government-funded health care from 2004 to 2013. We observed a $4.9 Billion decrease in health care expenditure from improving healthy living over the ten-year study. For more information, see the report here.

Air Pollution for Life Expectancy Calculator

The effect of long-term exposure to air pollution and risk of dying was examined for over 2.5 million Canadian adults who completed the 1991 long-form census. People were followed for over 36 million person-years, with over 300 000 deaths observed. Residential postal codes of person for each year, during sixteen years of follow-up, allowed Dr. Crouse and his collaborators to estimate each person’s exposure to fine particulate matter (PM2.5), ozone (O3), and nitrogen dioxide (NO2). Annual average pollutant concentrations were derived from data from ground-based air pollution monitors, satellite measurements, and atmospheric models. For more information about the study see ehp.niehs.nih.gov.

Nursing Home Calculator

The nursing home calculator was developed using a statistical model to estimate the risk of death and hospital admission for 53,739 people newly admitted to long-term care facilities in Ontario. We measured adjusted rates of hospital admissions and mortality, per 1000 person-years (PY) of follow-up, among for-profit and not-for-profit facilities at 3, 6, and 12 months post-admission. Rates were measured post-admission and until discharge or death, whichever came first. For more information about the study see www.jamda.com.

Salt Calculator

Developing a Web-based dietary sodium screening tool for personalized assessment and feedback. For more information about the study see www.ncbi.nih.gov.

Hospital Use Calculator

900,000 Days in Hospital: The annual impact of smoking, alcohol, diet, and physical activity on hospital use in Ontario. The hospital use calculator is from this report. For more information see www.ices.ca.

Algorithm viewer

The CVDPoRT algorithm viewer shows how each predictor contributes to overall risk. Many of the predictors are included as continuous exposures using restrictive cubic splines with age interaction. The algorithm viewer was created to explore the relationship between these exposures and the predicted 5-year risk of cardiovascular disease.