How does evidence based medicine impact infection control?

Evidence based medicine requires the integration of research evidence and clinical expertise in addition to patients´ values. However, regarding infection control practice, valid and clinically relevant research evidence is addressed to benefit not only patients but also communities by limiting the spread of infections, improving health care practices and preserving the health of communities.

What elements of evidence based medicine are necessary for infection prevention and control?

The elements of infection control and evidence based medicine needed to be need to for prevention and control are the definition of a relevant research question, the appropriate selection of a study design and a conduct and analysis minimizing bias.

What are the conclusions from clinical trials or meta-analyses related to infection control and evidence based medicine that guide infection control practices and policies?

Infection control policies are based on scientific sound research. In order to produce sound research, investigation should be patient-centered and aimed to evaluate the accuracy of diagnostic tests, the power of prognosis markers, the effectiveness and safety of therapies and of preventive practices. Valid (closeness to the truth), relevant (usefulness for clinical practice), and impact (size of the effect) are the three basic components of scientific sound research.

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What are the consequences of ignoring evidence based medicine as it is related to infection control?

The consequences of ignoring key concepts related to infection control and the use of evidence based medicine are the production of flawed research. Flawed research is characterized by lack of:

  • A clear formulated question in terms of population, intervention, comparison group and outcome analyzed

  • Errors in study design and conduct analysis leading to bias assessment of the truth (systematic error) and

  • Sample size not properly assessed in advance leading to a large ß error (random error)

What other information supports research regarding infection control and the use of evidence based medicine?

Most information regarding preventive or therapeutic measures in infection control should be based on randomized controlled trials. Randomized controlled trials are expensive and not always feasible. Some infection control recommendations have been based on ecologic studies comparing exposed and unexposed populations o in before and after studies. However, for etiologic assessments the appropriate study design is a case control study. Finally, cohort studies are the study design addressing questions on prognosis assessment.

Summary of current controversies.

Current controversies regarding infection control and the use of evidence based medicine are related in some cases by the need to put in practice preventive or therapeutic measures not proven yet. That may occur in ongoing epidemics or in those epidemics caused by unknown microorganisms requiring a fast put in action measures. In addition, hypothetical disasters like bioterrorism require plans based on theoretical grounds with no prior information to access in the literature. Finally, economical or personnel constraints can limit the applicability of well known infection control practices in some settings.

What is the impact of evidence based medicine relative to the impact of other aspects of infection control?

Evidence should guide all the approaches to infection control, but we need to admit that in many areas we have little or no evidence.

Controversies in detail.

Evidence based medicine is often summarized in documents classified as clinical practice guidelines. Clinical practice guidelines are defined as “systematically developed statements to assist practitioner and patient decisions about appropriate health care for specific clinical circumstances”. Over the last decade, several organizations have developed practice guidelines to improve quality, appropriateness, and cost-effectiveness of health care. In response to the increasing number of guidelines published, major medical organizations such as the American Medical Association and the Canadian Medical Association have carefully established methodological standards for clinical guidelines.

A review of the medical literature on 279 guidelines found that the adherence to standards was around 50%. Authors used a 25-item instrument to measure the frequency of adherence. Major guideline deficiencies were related with the following: lack of specification of outcomes of interest, failure to describe the population to which the guideline was applied, and the intended audience of the guideline. Most guidelines specified the preventive, diagnostic or therapeutic options available to clinicians and patients.

The following lists describe the methodological standards on guideline development.


  • Purpose of the guideline is specified

  • Rationale and importance of the guideline are explained

  • The participants in the guideline development process and their areas of expertise are specified

  • Targeted health problem or technology is clearly defined

  • Targeted patient population is specified

  • Intended audience or users of the guideline are specified

  • The principal preventive, diagnostic, or therapeutic options available to clinicians and patients are specified

  • The health outcomes are specified

  • The method by which the guideline underwent external review is specified

  • An expiration date or date of scheduled review is specified


  • Method of identifying scientific evidence is specified

  • Time period from which evidence is reviewed is specified

  • The evidence used is identified by citation and referenced

  • Method of data extraction is specified

  • Method for grading or classifying the scientific evidence is specified

  • Formal methods of combining evidence or expert opinion are used and described

  • Benefits and harms of specific health practices are specified

  • Benefits and harms are quantified

  • The effect on health care costs from specific health practices is specified

  • Costs are quantified


  • The role of value judgments used by the guideline developers in making recommendations is discussed

  • The role of patient preferences is discussed

  • Recommendations are specific and apply to the stated goals of the guideline

  • Recommendations are graded according to the strength of the evidence

  • Flexibility in the recommendations is specified

What national and international guidelines related to infection control and evidence based medicine exist?

The following list summarizes those national and international guidelines related to infection control and the use of evidence based medicine:

Intravascular catheter-related infections

Memel, LA, Allon, M, Bouza, E, Craven, DE, Flynn, P, O’Grady, NP, Raad, II, Rijnders, BJ, Sherertz, RJ, Warren, DK. “Clinical practice guidelines for the diagnosis and management of intravascular catheter-related infection: 2009 Update by the Infectious Diseases Society of America”. Clin Infect Dis. vol. 49. 2009 Jul 1. pp. 1-45.

Wolf, HH, Leithäuser, M, Maschmeyer, G, Salwender, H, Klein, U, Chaberny, I, Weissinger, F, Buchheidt, D, Ruhnke, M, Egerer, G, Cornely, O, Fätkenheuer, G, Mousset, S. “Infectious Diseases Working Party (AGIHO) f the German Society of Hematology and Oncology (DGHO). Central venous catheter-related infections in hematology and oncology: guidelines of the Infectious Diseases Working Party (AGIHO) of the German Society of Hematology and Oncology (DGHO)”. Ann Hematol. vol. 87. 2008 Nov. pp. 863-76.

Catheter-urinary tract infections

Hooton, TM, Bradley, SF, Cardenas, DD, Colgan, R, Geerlings, SE, Rice, JC, Saint, S, Schaeffer, AJ, Tambayh, PA, Tenke, P, Nicolle, LE. “Infectious Diseases Society of America. Diagnosis, prevention, and treatment of catheter-associated urinary tract infection in adults: 2009 International Clinical Practice Guidelines from the Infectious Diseases Society of America”. Clin Infect Dis. vol. 50. 2010 Mar 1. pp. 625-63.

Nosocomial pneumonia

Muscedere, J, Dodek, P, Keenan, S, Fowler, R, Cook, D, Heyland, D. “VAP Guidelines Committee and the Canadian Critical Care Trials Group. Comprehensive evidence-based clinical practice guidelines for ventilator-associated pneumonia: prevention”. J Crit Care. vol. 23. 2008 Mar. pp. 126-37.

Tablan, OC, Anderson, LJ, Besser, R, Bridges, C, Hajjeh, R. “CDC; Healthcare Infection Control Practices Advisory Committee. Guidelines for preventing health-care–associated pneumonia, 2003: recommendations of CDC and the Healthcare Infection Control Practices Advisory Committee. MMWR Recomm Rep. 2004 Mar 26;53(RR-3):1-36.American Association for Respiratory Care. AARC Clinical Practice Guidelines. Endotracheal suctioning of mechanically ventilated patients with artificial airways 2010”. Respir Care. vol. 55. 2010 Jun. pp. 758-64.

Surgical site infection

Mangram, AJ, Horan, TC, Pearson, ML, Silver, LC, Jarvis, WR. “Guideline for Prevention of Surgical Site Infection, 1999. Centers for Disease Control and Prevention (CDC) Hospital Infection Control Practices Advisory Committee”. Am J Infect Control. vol. 27. 1999 Apr. pp. 97-132.

Prophylaxis and treatment of methicillin-resistant Staphylococcus aureus infection

Gould, FK, Brindle, R, Chadwick, PR, Fraise, AP, Hill, S, Nathwani, D, Ridgway, GL, Spry, MJ, Warren, RE. “MRSA Working Party of the British Society for Antimicrobial Chemotherapy. Guidelines (2008) for the prophylaxis and treatment of Methicillin-resistant Staphylococcus aureus (MRSA) infections in the United Kingdom”. J Antimicrob Chemother. vol. 63. 2009 May. pp. 849-61.


“Healthcare Infection Control Practices Advisory Committee and Hand-Hygiene Task Force; Society for Healthcare Epidemiology of America; Association for Professionals in Infection Control and Epidemiology; Infection Diseases Society of America. Guideline for hand hygiene in healthcare settings”. J Am Coll Surg. vol. 198. 2004 Jan. pp. 121-7.


Stuart, RL, Cheng, AC, Marshall, CL, Ferguson, JK. “Healthcare infection control special interest group of the Australian Society for infectious Diseases. ASID (HICSIG) position statement: infection control guidelines for patients with influenza-like illnesses, including pandemic (H1N1) influenza 2009, in Australian health care facilities”. Med J Aust. vol. 191. 2009 Oct 19. pp. 454-8.

What other consensus group statements exist and what do key leaders advise?

CDC, and additional information can be found from the University of North Caroline webpage on several issues related to prevention of healthcare-associated Infections.


Strauss, SE, Richardson, WS, Glasziou, P, Haynes, RB. “Evidence based medicine. How to practice and teach EBM. Third edition. Elsevier Churchill Livingstone”. Edinburgh. 2005. (This book is for clinicians at any stage who want to know how to practice and teach evidence based medicine. The book emphasizes direct clinical application of EBM and tactics to practice EBM in real-time.)

Guyatt, GH, Rennie, D, Meade, MO, Cook, DJ. Users´ guide to the medical literature. A manual for evidence-based clinical practice. 2008. (The book describes how to apply medical literature to clinical practice. The book covers the basic principles on how to identify and use medical literature, the philosophy of evidence-based medicine, the research question and assessment of studies in terms of bias and random error.)

Eddy, DM. A Manual for Assessing Health Practices and Designing Practice Policies: The Explicit Approach. 1992. (American Medical Association methodological standards for developing practice guideline.)

American Medical Association, Office of Quality Assurance. Attributes to Guide the Development and Evaluation of Practice Parameters. 1990. (American Medical Association methodological standards for developing practice guideline.)

Woolf, SH. Manual for Clinical Practice Guideline Development. 1991. pp. 91-0007. (American Medical Association methodological standards for developing practice guideline.)

Quality of Care Program: The Guidelines for Canadian Clinical Practice Guidelines. 1993. (Canadian Medical Association methodological standards for developing practice guideline.)

Shaneyfelt, TM, Mayo-Smith, MF, Rothwangl, J. “Are guidelines following guidelines? The methodological quality of clinical practice guidelines in the peer-reviewed medical literature”. JAMA. vol. 281. 1999 May 26. pp. 1900-5. (A systematic review assessing the methodological quality of already published clinical practice guidelines of Evidence Based Medicine.)