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Impact of the NICE guideline recommending cessation of antibiotic prophylaxis for prevention of infective endocarditis: before and after study

BMJ 2011; 342 doi: (Published 03 May 2011) Cite this as: BMJ 2011;342:d2392
  1. Martin H Thornhill, professor of oral medicine1,
  2. Mark J Dayer, consultant cardiologist2,
  3. Jamie M Forde, information analyst3,
  4. G Ralph Corey, Gary Hock professor in global health4,
  5. Vivian H Chu, assistant professor4,
  6. David J Couper, deputy director5,
  7. Peter B Lockhart, chair6
  1. 1University of Sheffield School of Clinical Dentistry, Sheffield S10 2TA, UK
  2. 2Department of Cardiology, Taunton and Somerset NHS Trust, Taunton, Somerset, UK
  3. 3Dr Foster Intelligence, London EC1A 9LA, UK
  4. 4Division of Infectious Diseases, Duke University Medical Centre, Durham, NC, USA
  5. 5Collaborative Studies Coordinating Center, Department of Biostatistics, University of North Carolina, USA
  6. 6Department of Oral Medicine, Carolinas Medical Center, Charlotte, NC, USA
  1. Correspondence to: M H Thornhill m.thornhill{at}
  • Accepted 17 February 2011


Objective To quantify the change in prescribing of antibiotic prophylaxis before invasive dental procedures for patients at risk of infective endocarditis, and any concurrent change in the incidence of infective endocarditis, following introduction of a clinical guideline from the National Institute for Health and Clinical Excellence (NICE) in March 2008 recommending the cessation of antibiotic prophylaxis in the United Kingdom.

Design Before and after study.

Setting England.

Population All patients admitted to hospital in England with a primary or secondary discharge diagnosis of acute or subacute infective endocarditis.

Main outcome measures Monthly number of prescriptions for antibiotic prophylaxis consisting of a single 3 g oral dose of amoxicillin or a single 600 mg oral dose of clindamycin, and monthly number of cases of infective endocarditis, infective endocarditis related deaths in hospital, or cases of infective endocarditis with a possible oral origin for streptococci.

Results After the introduction of the NICE guideline there was a highly significant 78.6% reduction (P<0.001) in prescribing of antibiotic prophylaxis, from a mean 10 277 (SD 1068) prescriptions per month to 2292 (SD 176). Evidence that the general upward trend in cases of infective endocarditis before the guideline was significantly altered after the guideline was lacking (P=0.61). Using a non-inferiority test, an increase in the number of cases of 9.3% or more could be excluded after the introduction of the guideline. Similarly an increase in infective endocarditis related deaths in hospital of 12.3% or more could also be excluded.

Conclusion Despite a 78.6% reduction in prescribing of antibiotic prophylaxis after the introduction of the NICE guideline, this study excluded any large increase in the incidence of cases of or deaths from infective endocarditis in the two years after the guideline. Although this lends support to the guideline, ongoing data monitoring is needed to confirm this, and further clinical trials should determine if antibiotic prophylaxis still has a role in protecting some patients at particularly high risk.


  • We thank Sue Eve-Jones, senior hospital statistics data coder at Taunton and Somerset NHS Trust for her advice and seed funding from Somerset Heart Research Fund.

  • Contributors: MHT and MJD contributed to all aspects of the study. PBL, GRC, and VHC contributed to the literature search, data interpretation, and writing of the manuscript. JMF was involved in data collection and interpretation. DJC was involved in the statistical analysis, data interpretation, and writing of the manuscript.

  • Funding: MJD received funding from the Somerset Health Research Fund to facilitate access to the data. The funder played no part in the design of the study, writing of the manuscript, or decision to submit the manuscript for publication. The other authors received no external funding for their contribution to this study.

  • Competing interests: All authors have completed the Unified Competing Interest form at (available on request from the corresponding author) and declare: (1) MJD received some financial support from the Somerset Health Research Fund; (2) in the last 3 years GRC has acted as a consultant and expert witness for Cubist Pharmaceuticals that might have an interest in the submitted work; (3) no other relationships or activities that could appear to have influenced the submitted work. None of the authors of this paper were members of the NICE guideline committee that introduced NICE guideline No 64. PBL, however, was a member of the 2007 guideline committee of the American Heart Association.

  • Ethical approval: Not required.

  • Data sharing: No additional data available.

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