Peter L Thompson,* Pamela J Bradshaw,† Margherita Veroni,‡ Edward T Wilkes§
* Cardiologist, † Clinical Research Coordinator, ‡ Epidemiologist, Western Australian Heart Research Institute, Sir Charles Gairdner Hospital, Nedlands, WA 6009; § Senior Research Fellow, Centre for Developmental Health, Telethon Institute for Child Health Research, Subiaco, WA. peter.thompsonAThealth.wa.gov.au
In reply: We appreciate the commentary by Wang and Hoy on the problems of the use of risk scores for assessing cardiovascular risk in Aboriginal people.
In general, we agree that caution is essential in using tables that predict absolute risk of cardiovascular events. However, despite their limitations, absolute risk estimates are being encouraged by Australian, European, New Zealand and US authorities as a practical aid to targeting coronary disease preventive measures.1 An estimated risk of > 15% of a fatal cardiovascular event within 10 years, based on the Sheffield or Framingham scores, is now recommended as an indication for active treatment. Our prime purpose in providing an estimate of absolute risk in the Perth urban Aboriginal population was to demonstrate that a program of cardiovascular risk assessment with strong Aboriginal community support is capable of detecting high-risk people who will benefit from intensive risk-lowering strategies.
Wang and Hoy’s caution about applying absolute risk estimates based on the Framingham population to unrelated populations is of particular importance in the case of Australian Indigenous people, in whom diabetes and the related metabolic syndrome may be the predominant risk factors.
We have recently completed an analysis of the determinants of carotid atherosclerosis in the same population described in our earlier study.2 Our results confirm that, while the Framingham estimates (based on sex, age, LDL cholesterol and blood pressure) are indeed predictors of carotid atherosclerosis, their predictive value is significantly enhanced by the addition of markers of diabetes status and obesity.
The 13-year follow-up study of the Aboriginal cohort referred to by Wang and Hoy will provide unique data to help identify reliable risk predictors specific to Aboriginal people, and we look forward to its publication.
- 1. Joint British recommendations on prevention of coronary heart disease in clinical practice. British Cardiac Society, British Hyperlipidaemia Association, British Hypertension Society, endorsed by the British Diabetic Association. Heart 1998; 80 (Suppl 2): S1-S29.
- 2. Thompson PL, Bradshaw PJ, Veroni M, Wilkes ET. Cardiovascular risk among urban Aboriginal people. Med J Aust 2003; 179: 143-146. <MJA full text>
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