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β Blockade after myocardial infarction: systematic review and meta regression analysis

BMJ 1999; 318 doi: (Published 26 June 1999) Cite this as: BMJ 1999;318:1730
  1. Nick Freemantle, senior research fellow (meg{at},
  2. John Cleland, professorb,
  3. Philip Young, lecturer in applied statisticsc,
  4. James Mason, senior research fellowa,
  5. Jane Harrison, information officera
  1. aMedicines Evaluation Group, Centre for Health Economics, University of York, York YO10 5DD
  2. bDepartment of Cardiology, Castle Hill Hospital, University of Hull, Kingston upon Hull, U16 5JQ
  3. cDepartment of Health Sciences and Clinical Evaluation, University of York
  1. Correspondence to: N Freemantle
  • Accepted 6 April 1999


Objectives: To assess the effectiveness of β blockers in short term treatment for acute myocardial infarction and in longer term secondary prevention; to examine predictive factors that may influence outcome and therefore choice of drug; and to examine the clinical importance of the results in the light of current treatment.

Design:Systematic review of randomised controlled trials.

Setting: Randomised controlled trials.

Subjects: Patients with acute or past myocardial infarction.

Intervention: βBlockers compared with control.

Main:outcome measures All cause mortality and non-fatal reinfarction.

Results: Overall, 5477 of 54 234 patients (10.1%) randomised to β blockers or control died. We identified a 23% reduction in the odds of death in long term trials (95% confidence interval 15% to 31%), but only a 4% reduction in the odds of death in short term trials (−8% to 15%). Meta regression in long term trials did not identify a significant reduction in effectiveness in drugs with cardioselectivity but did identify a near significant trend towards decreased benefit in drugs with intrinsic sympathomimetic activity. Most evidence is available for propranolol, timolol, and metoprolol. In long term trials, the number needed to treat for 2 years to avoid a death is 42, which compares favourably with other treatments for patients with acute or past myocardial infarction.

Conclusions: β Blockers are effective in long term secondary prevention after myocardial infarction, but they are underused in such cases and lead to avoidable mortality and morbidity.


  • Funding SmithKline Beecham Pharmaceuticals UK. The views expressed are those of the authors and not necessarily those of the sponsor.

  • Competing interests This study was funded through an unrestricted educational grant by SmithKline Beecham, who supply carvedilol in the United States. JGFC has spoken at many meetings and educational programmes on drugs in heart failure, organised by pharmaceutical and device companies, and received fees and expenses. He has also received research funding from industry as well as the NHS, British Heart Foundation, and US Veterans Administration.

  • website extra: References for the trials appear on the BMJ's website

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