How were the rapid reviews of the evidence summaries conducted?

The National Vascular Disease Prevention Alliance (NVDPA) Guidelines for the Management of Absolute Cardiovascular Risk and Dynamed Clinical summaries served as the initial secondary sources for each evidence summary. A peer review literature search of Medline was then conducted using appropriate Medical Subject Heading terms for journal articles published after the latest article in either the Guideline or Dynamed summary.

A journal article was selected if it was of higher quality than the evidence cited in either the Guidelines or Dynamed summary. This was primarily decided on the basis of study type (i.e. NHMRC levels of evidence: systematic review > randomised controlled trial > observational cohort study). The final selection was approved by academic GP experts in the ASK-GP Centre of Research Excellence before publishing to this website.

How are the risk factors used to calculate absolute cardiovascular risk?

The 5 year Framingham Risk Equation is used to calculate the absolute risk of a cardiovascular disease event based on Australian Guidelines. This model found the most predictive factors were: Sex, Age, Diabetes, Smoking status, Total-to-HDL Cholesterol ratio, Systolic Blood Pressure, and ECG-LVH. Obesity was not found to be predictive after taking cholesterol and blood pressure into account.

What about other risk factors like family history?

Other risk factors such as family history are still important for CVD prevention, but they are taken into account at the management stage rather than the absolute risk algorithm. For example, a moderate risk patient with a strong family history is recommended to take medication at an earlier stage under Australian guidelines. This determines the recommended management results in the risk calculator.

For further reading on the model see: Anderson KM, Odell PM, Wilson PW, Kannel WB. Cardiovascular disease risk profiles. American heart journal. 1991 Jan 1;121(1):293-8. PMID: 1985385

How are automatic high risk cases identified?

The National Vascular Disease Prevention Alliance (NVDPA) Guidelines for the Management of Absolute Cardiovascular Risk provides a set of factors that automatically deem an individual at high risk of cardiovascular disease in the next 5 years (e.g. diabetic over 60 years). These have been incorporated into the calculator.

If a case is deemed high risk they are not provided with a numeric risk result and thus would not be able to see the effect of an intervention on their personalised risk of CVD.

How are the intervention effects estimated?

The effect of quitting smoking is calculated by running the Framingham risk assessment algorithm again as a non-smoker. The other intervention effects are estimated by a single study with the best level of evidence (typically a systematic review) that arose from the rapid review. The relative risks are provide below:

Intervention Relative Risk Reference
Blood Pressure Lowering Medication 0.85 Blood Pressure Lowering Treatment Trialists’ Collaboration. Blood pressure-lowering treatment based on cardiovascular risk: a meta-analysis of individual patient data. The Lancet. 2014 Aug 22;384(9943):591-8.
Statins (Chol Medication) 0.75 Taylor F, Huffman MD, Macedo AF, Moore TH, Burke M, Davey Smith G, Ward K, Ebrahim S. Statins for the primary prevention of cardiovascular disease. The Cochrane Library. 2013 Jan 1.
Aspirin 0.88 Raju N, Sobieraj-Teague M, Hirsh J, O’Donnell M, Eikelboom J. Effect of aspirin on mortality in the primary prevention of cardiovascular disease. The American journal of medicine. 2011 Jul 31;124(7):621-9
Mediterranean Diet 0.71 Martinez-Gonzalez MA, Salas-Salvado J, Estruch R, Corella D, Fito M, Ros E,  Benefits of the Mediterranean Diet: Insights from the PREDIMED Study. Progress in cardiovascular diseases, 2015 Aug 31;58(1):50-60
Physical Activity 0.75 “Li J, Siegrist J: Physical activity and risk of cardiovascular disease–a meta-analysis of prospective cohort studies. International journal of environmental research and public health 2012;9(2):391-407
Fish Oil (Omega-3) Supplements Not significant Rizos EC, Ntzani EE, Bika E, Kostapanos MS, Elisaf MS. Association between omega-3 fatty acid supplementation and risk of major cardiovascular disease events: a systematic review and meta-analysis. JAMA. 2012 Sep 12;308(10):1024-33.
Antioxidant supplements Not significant Bjelakovic G, Nikolova D, Gluud LL, Simonetti RG, Gluud C. Antioxidant supplements for prevention of mortality in healthy participants and patients with various diseases. The Cochrane Library. 2012 Jan 1.
Multivitamins Not significant Sesso HD, Christen WG, Bubes V, Smith JP, MacFadyen J, Schvartz M, Manson JE, Glynn RJ, Buring JE, Gaziano JM. Multivitamins in the prevention of cardiovascular disease in men: the Physicians’ Health Study II randomized controlled trial. JAMA. 2012 Nov 7;308(17):1751-60.

Funding Sources and Affiliations

This website was funded by the Heart Foundation, Royal Australian College of General Practitioners and Therapeutic Guidelines Limited in 2016-2018, and developed by:

  • Dr Carissa Bonner, Behavioural Scientist and NHMRC/Heart Foundation Research Fellow at the University of Sydney
  • Professor Lyndal Trevena, Primary Health Care and Head of the Discipline of General Practice at the University of Sydney
  • Professor Jenny Doust, Professor of Clinical Epidemiology in the Centre for Research in Evidence Based Practice at Bond University
  • Professor Kirsten McCaffery, Professorial Research Fellow at the School of Public Health and a NHMRC Career Development Fellow
  • Michael Fajardo, Research Assistant at the School of Public Health for the ASK-GP CRE

The website is also supported by a Centre of Research Excellence funded by the NHMRC: the ASK-GP CRE (Ask, Share Know: Rapid Evidence for General Practice Decisions). The ASK-GP CRE is a collaboration between Bond University and The University of Sydney, led by internationally renowned academics across the fields of general practice, evidence-based medicine, shared decision making, guideline development and knowledge translation (including Professors Trevena, Doust and McCaffery). For more information about the ASK-GP CRE click here.