Volume 180 - Issue 4
Prevention of cardiovascular disease: an evidence-based clinical aid
Author: Neil H Cradick
Med J Aust 2004; 180 (4): 197-198. || doi: 10.5694/j.1326-5377.2004.tb05873.x
Published online: 16 February 2004
Published online: 16 February 2004
To the Editor: On opening the MJA Focus document “Prevention of cardiovascular disease: an evidence-based clinical aid”,1 I expected to find useful and contemporary guidelines for general practice. However, I was surprised to read two of the recommendations — for the use of antihypertensive and antiplatelet drugs in “low risk” patients (those without risk-associated clinical conditions or end-organ damage).
The document recommends drug treatment only if systolic blood pressure is > 180 mmHg or diastolic blood pressure is > 100 mmHg in people under 60 years, or systolic blood pressure is > 160 mmHg in people over 60 years. While Fulcher et al1 volunteered that this was at odds with clinical practice, they supported the recommendations by stating that they were in accordance with published guidelines. The data for these conservative hypertension parameters were published nearly 10 years ago,2 or derived from textbooks,3 and are at odds with the 1999 WHO/ISH guidelines,4 and even more at odds with the excellent Joint National Committee (JNC 7) report.5 The latter publication recommends, after lifestyle recommendations, drug treatment for a blood pressure of 140–159/90–99 mmHg for those without end-organ damage.
Furthermore, the focus document recommends primary prevention with aspirin in those with a calculated annual cardiovascular event risk > 3%. Hayden et al6 suggest antiplatelet treatment should be offered to those with a 5-year cardiovascular event risk > 3%, which equates to a > 0.6% annual risk. The benefit to harm ratio needs to be explained to the individual, and therapy should only be initiated once blood pressure is controlled.
As an interested general practitioner and user of evidence-based guidelines, I usually check the funding of publications, and, with the heavy emphasis on the use of ACE inhibitors (in particular ramipril) and statins (which are produced by Aventis Pharma), it is difficult to rely on the evidence as presented. I would hope that independent bodies such as the National Prescribing Service or Australian Prescriber could take the pharmaceutical lead and produce desktop references with a more unbiased opinion on the latest collection of evidence that is shaking us up in primary care medicine.
I would again refer readers to the excellent hypertension guidelines mentioned above4,5 (in particular the JNC 7 reference card available on the Internet at www.nhlbi.nih.gov/guidelines/hypertension/jnc7card.htm), and caution them to remain wary of easy-reference desktop items funded by pharmaceutical companies.
References
- Fulcher GR, Conner GW, Amerena JV, et al. Prevention of cardiovascular disease: an evidence-based clinical aid [Focus document]. Med J Aust 2003; 179 (21 July): 1-16. <eMJA full text>
- The management of hypertension: a consensus statement. Med J Aust 1994; 160 (6 Suppl): S1-S16. i1082907
- Wood D, de Backer G, Faergeman O, et al. Clinicians’ manual on total risk management. In: Davenport L, editor. A guide to prevention of coronary heart disease. London: Science Press, 2000. i1082909
- Guidelines Subcommittee. 1999 World Health Organization — International Society of Hypertension. Guidelines for the management of hypertension. J Hypertens 1999; 17: 151-183. i1082911
- Chobanian AV, Bakris GL, Black HR, et al. The Seventh report of the Joint National Committee on Prevention, Detection, Evaluation and Treatment of high blood pressure: the JNC 7 report. JAMA 2003; 289: 2560-2572. i1082913
- Hayden M, Pignone M, Phillips C, Mulrow C. Aspirin for the primary prevention of cardiovascular events: a summary of the evidence for the US Preventive Services Task Force. Ann Intern Med 2002; 136: 161-172. i1082915