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Review: β blockers differ in their efficacy for preventing major cardiovascular events in younger and older patients
  1. Robert Weiss, MD
  1. Androscoggin Cardiology Associates,
 Auburn, Maine, USA

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 Q When used as first line treatment of hypertension, does the efficacy of β blockers for preventing major cardiovascular events differ between younger and older patients?

    Clinical impact ratings GP/FP/Primary care ★★★★★☆☆ IM/Ambulatory care ★★★★★★★ Cardiology ★★★★★★☆

    METHODS

    Embedded ImageData sources

    PubMed (1950 to January 2006), reference lists of hypertension meta-analyses, and experts.

    Embedded ImageStudy selection and assessment

    randomised controlled trials (RCTs) with blinded assessment of outcome that compared β blockers with placebo or other antihypertensive drugs as first line therapy for hypertension. 21 RCTs met the selection criteria: 10 trials (n = 50 612) involved younger patients (mean age 46–56 y), and 11 trials (n = 95 199) involved older patients (mean age 60–76 y).

    Embedded ImageOutcomes

    a composite end point of stroke, myocardial infarction (MI), or death; stroke; MI; death; and heart failure.

    MAIN RESULTS

    In younger patients, β blockers reduced risk of the composite end point more than placebo and did not differ from other antihypertensive drugs (table). In older patients, β blockers did not differ from placebo for the composite end point and increased risk more than other antihypertensive drugs (table). In younger patients, β blockers did not differ from placebo or other antihypertensive drugs for the individual outcomes of stroke, MI, death, or heart failure. In older patients, β blockers reduced risk of stroke (relative risk reduction [RRR] 22%, 95% CI 2 to 37) and heart failure (RRR 46%, CI 19 to 63) more than placebo (groups did not differ for MI or death), but were associated with increased risk of stroke (relative risk increase 18%, CI 7 to 30) compared with other antihypertensive drugs (groups did not differ for MI, death, or heart failure).

    β blockers as first line treatment of hypertension in preventing the composite end point in younger and older patients*

    CONCLUSIONS

    When used as first line treatment of hypertension, β blockers are more effective than placebo in younger patients, but not in older patients. β blockers have similar efficacy to other antihypertensive drugs in younger patients but are less effective than such drugs in older patients.

    Abstract and commentary also appear in ACP Journal Club.

    Commentary

    Some guidelines now state that β blockers are not preferred initial antihypertensive therapy for patients without other indications (eg, angina) for their use.1 Others suggest that β blockers may still be recommended for first line treatment of hypertension for patients <60 years of age, presumably based in part on the systematic review by Khan et al.2 All guidelines recommend thiazides as a first line choice and calcium channel blockers as an alternative. Another point of controversy is whether the β blocker in this situation really means atenolol, since it was the drug used in most β blocker hypertension trials.

    How does the review by Khan and McAlister help us? Although the review created a cutoff age of 60 years “because the pathophysiology of hypertension differs in older and younger patients,” this notion is contentious. Isolated systolic hypertension is the diagnosis in >85% of patients >60 years of age compared with only 25% in those <50 years, but it is important to note that those 50–59 years are a mixed group.3 Furthermore, there is no RCT of hypertension treatment stratified by age to support the notion of differing pathophysiological mechanisms.

    The issue of β blockers as initial therapy remains unresolved in practice as well. In a review of a Medicaid database from 2001–2005, the use of β blockers as initial therapy remained consistently at 25% in a population of 5373 patients with newly diagnosed hypertension, seemingly uninfluenced by recent guidelines.4 This finding may indicate that physicians have other reasons for prescribing β blockers (including perseveration), the newer guideline messages have not yet been communicated well, or physicians simply do not buy the message.

    References

    View Abstract

    Footnotes

    • For correspondence: Dr F McAlister, University of Alberta Hospital, Edmonton, Alberta, Canada. finlay.mcalister{at}ualberta.ca

    • Source of funding: no external funding.