Estimating atherosclerotic cardiovascular disease risk

Australian Chronic Disease Prevention Alliance 2023

The Aus CVD risk calculator is the most appropriate tool for estimating risk in the Australian context. ASCVD risk factors and how they are factored into the risk estimation are outlined in Risk factors for ASCVD and their application in the Aus CVD risk calculator; they are divided into 4 categories:

  • ASCVD risk factors that automatically confer high risk: People with familial hypercholesterolaemia or chronic kidney disease are considered to be at clinically determined high risk of a cardiovascular event and do not require formal risk calculation using the calculator.
  • ASCVD risk factors considered in the initial risk calculation: The first step in using the risk calculator is to enter information about the primary drivers of risk; additional information is collected for people with type 2 diabetes to refine their risk. From these factors, the calculator gives an initial risk estimate of high, intermediate or low.
  • ASCVD risk factors that can be used to reclassify risk: Reclassification to a higher or lower risk category can then be considered in people with certain additional risk factors, to provide a more accurate risk estimate. Reclassification factors are especially relevant if the initial calculated risk is close to a higher or lower threshold, particularly if the initial calculated risk is intermediate, as a small shift may mean their risk estimate falls into a different risk category. This may affect management decisions.
  • ASCVD risk factors not included in the risk estimation: The risk calculator uses factors for which the influence on ASCVD risk has been quantified and validated. Many other comorbidities, lifestyle factors and patient circumstances are associated with ASCVD risk. These factors should be considered as part of a holistic patient assessment, but have not been specifically identified as modifying the estimated risk category.
Table 1. Risk factors for ASCVD and their application in the Aus CVD risk calculator

ASCVD risk factors that automatically confer high risk

familial hypercholesterolaemia

moderate to severe chronic kidney disease [NB1]

ASCVD risk factors considered in the initial risk calculation

increasing age

male sex

smoking

elevated blood pressure

dyslipidaemia

use of CVD medicines (blood pressure-lowering, lipid-modifying, antithrombotic) within the last 6 months [NB2]

atrial fibrillation

lower socioeconomic status [NB3]

diabetes [NB4] [NB5]

ASCVD risk factors that can be used to reclassify risk

Reclassification factors can have varying effects on risk estimates:

  • ethnicity:
    • consider reclassification to a higher risk category for First Nations, Mӓori, or Pacific Islander peoples, or for people of South Asian (Indian, Pakistani, Bangladeshi, Sri Lankan, Nepali, Bhutanese or Maldivian) ethnicity
    • consider reclassification to a lower risk category for people of East Asian (Chinese, Japanese, Taiwanese or Mongolian) ethnicity
  • family history of premature CVD: defined as cardiovascular disease or stroke occurring in a first-degree female relative aged less than 65 years, or a first-degree male relative aged less than 55 years; consider reclassification to a higher risk category
  • mild chronic kidney disease: associated with increased risk of CVD; strongly consider reclassification to a higher risk category (people with moderate to severe chronic kidney disease are clinically determined to be at high risk)
  • severe mental illness: defined as a current or recent mental health condition requiring specialist treatment (whether or not that treatment was received) in the last 5 years; consider reclassification to a higher risk category
  • coronary artery calcium (CAC) scoring: a computed tomography (CT) scan evaluating the amount of calcified plaque in the coronary arteries. Results may indicate a greater or lesser extent of coronary atherosclerosis; consider reclassification to a higher or lower risk category respectively [NB6].

ASCVD risk factors not included in the risk calculator [NB7]

chronic immune-mediated inflammatory disorders (eg rheumatoid arthritis)

COVID-19

preeclampsia, pregnancy-related hypertension and gestational diabetesGunderson, 2021

premature ovarian insufficiency or early menopause

central obesity

poor nutrition

sedentary lifestyle

social deprivation

obstructive sleep apnoea

drugs that worsen cardiovascular risk factors (eg drugs that increase blood pressure)

nonalcoholic fatty liver disease

treatment for human immunodeficiency virus infection

Note:

ACDPA = Australian Chronic Disease Prevention Alliance

NB1: For the purposes of ASCVD risk assessment, moderate to severe chronic kidney disease is defined as sustained estimated glomerular filtration rate (eGFR) less than 45 mL/min/1.73 m2, or persistent albuminuria (urine albumin–creatinine ratio [uACR] above 25 mg/mmol for men or above 35 mg/mmol for women).

NB2: BP-lowering, lipid-modifying and antithrombotic medicines are indicated for a wide range of conditions, including non-cardiovascular conditions such as migraine. Consequently, people may be prescribed these medicines despite not having had formal CVD risk assessment. Because treatment with these medicines can modify other CVD risk factors (eg reduce blood pressure or cholesterol), the Aus CVD risk calculator adjusts for medicine use in assessment of a patient’s risk.

NB3: The Aus CVD risk calculator uses Socioeconomic Indexes for Areas (SEIFA) quintiles obtained from residential postcodes as a measure of socioeconomic status. These can be adjusted within the calculator if the postcode does not provide an accurate representation of a person’s socioeconomic status.

NB4: The same risk factors influence risk in people with type 1 diabetes as in those with type 2 diabetes; however, the Aus CVD risk calculator is not validated for use in people with type 1 diabetes.

NB5: For people with type 2 diabetes, additional information is requested by the calculator to refine risk (years since diagnosis, glycated haemoglobin, uACR, eGFR, BMI, insulin use).

NB6: Coronary artery calcium scoring is not subsidised by the Medicare Benefits Schedule and should not be performed in patients with established ASCVD, those at high ASCVD risk, or those who have already started lipid-modifying therapy. For more information on coronary artery calcium scoring, see the Heart Foundation position statementJennings, 2021Lin, 2018Peters, 2012.

NB7: There are many risk factors associated with ASCVD risk; this is not an exhaustive list. These factors should be considered as part of a holistic patient assessment but have not been specifically identified as modifying the estimated risk category.

Source: Australian Chronic Disease Prevention Alliance. Australian Guideline for assessing and managing cardiovascular disease risk. Melbourne: National Heart Foundation of Australia; 2023. https://www.cvdcheck.org.au/