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Can Fam Physician
Vol. 53, No. 5, May 2007, pp.800 - 801
Copyright © 2007 by The College of Family Physicians of Canada
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Debates

Rebuttal: Do β-blockers have a role in treating hypertension?

YES

Nadia Khan, MD FRCPC MSc
Assistant Professor at the Centre for Health Evaluation and Outcomes Sciences in the Division of General Internal Medicine at the University of British Columbia in Vancouver

Finlay A. McAlister, MD FRCPC MSc
Associate Professor in the Division of General Internal Medicine at the University of Alberta in Edmonton

One of the serious public health problems in Canada today is inadequate blood pressure (BP) control among patients with hypertension.1 Thus, we need to be very careful before we remove efficacious agents—with which clinicians are familiar and comfortable—from the antihypertensive armamentarium.

We agree with Dr McCormack that β-blockers are not efficacious among the elderly, and these drugs should be avoided as initial monotherapy in this group. Contrary to Dr McCormack’s assertion, however, we do see many patients for whom the "2-fer" potential of β-blockers makes them attractive add-ons (eg, patients with hypertension and heart failure or angina).

Dr McCormack disagrees with our assertion that β-blockers are efficacious in preventing cardiovascular events in younger patients when tested as monotherapy. Although he acknowledges that the relative risk reduction in cardiovascular events with β-blockers versus placebo in the 2 trials enrolling younger patients was 14% and statistically significant (relative risk [RR] 0.86; 95% confidence interval [CI] 0.746–0.996; P = .04),2 he points out that the absolute risk reduction was only 0.5% and thus believes use of this agent is not warranted. The savvy reader will be aware, however, that absolute risk reductions are driven largely by baseline risk, and very few preventive therapies look appealing in younger patients if one focuses solely on the absolute risk reduction. For example, in the Medical Research Council trial of treatment of mild hypertension alluded to by Dr McCormack (one of the few placebo-controlled trials that tested the efficacy of thiazide diuretics in young patients with mild hypertension; mean age 52 years and mean BP 161/98 mm Hg), thiazide diuretics reduced the relative risk of cardiovascular events by 21% (RR 0.79; 95% CI 0.65–0.97; P = .02), but this translated into an absolute risk reduction of only 0.8%.3 Would Dr McCormack then advocate against the use of thiazide diuretics in younger hypertensive patients on the basis of this modest absolute risk reduction? We wouldn’t.

In the treatment of hypertension, the key points for clinicians to remember are as follows:

  • lowering BP prevents cardiovascular events,
  • greater reductions in BP translate into greater benefits,
  • most of the differences in benefits seen between drug classes in active-control trials are due to differences in degree of BP lowering achieved,4 and
  • most hypertensive patients require more than one agent to achieve optimal BP control.

References

  1. Joffres MR, Ghadirian P, Fodor JG, Petrasovits A, Chockalingam A, Hamet P. Awareness, treatment, and control of hypertension in Canada. Am J Hypertens 1997;10:1097-102.[Medline]
  2. Khan N, McAlister FA. Re-examining the efficacy of β-blockers for the treatment of hypertension: a meta-analysis. CMAJ 2006;174:1737-42.[Abstract/Free Full Text]
  3. Medical Research Council Working Party. MRC trial of treatment of mild hypertension: principal results. Br Med J (Clin Res Ed) 1985;291:87-104.
  4. Staessen JA, Wang JG, Thijs L. Cardiovascular prevention and blood pressure reduction: a quantitative overview updated until 1 March 2003. J Hypertens 2003;21(6):1055-76.[Medline]

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Changing fear
Diane Kelsall
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Réfutation: Les bêtabloquants ont-ils un rôle dans le traitement de l’hypertension?: OUI
Nadia Khan and Finlay A. McAlister
CFP 2007 53: 802-803. [Full Text]  

Réfutation: Les bêtabloquants ont-ils un rôle dans le traitement de l’hypertension?: NON
James P. McCormack
CFP 2007 53: 802-803. [Full Text]  




This Article
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