Cath Lab Digest

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Evidence-based Medicine: Efficacy and Effectiveness
  Levels of evidence. Evidence-based medicine is the “conscientious, explicit and judicious use of current best evidence in making decisions about the care of individual patients.”¹⁷ The practice of evidence-based medicine integrates individual clinical expertise with the best available external clinical evidence from systematic research.¹⁷ Advocates of evidence-based medicine classify studies according to levels of evidence on the basis of the research design^18-20 (see Table 1). In the hierarchy of research design, the results of randomized, controlled trials and meta-analyses of randomized controlled trials are considered to be evidence of the highest grade for the majority of clinical or interventional questions; whereas, observational studies fall at intermediate levels because they reportedly overestimate treatment effects and descriptive studies (eg, case series) and expert opinion receive the lowest levels.^18-20 Although study quality is sometimes evaluated within each level, each category is considered methodologically superior to those below it.¹⁸ This hierarchical approach to study design has been promoted widely in individual reports, meta-analyses, consensus statements, and educational materials for healthcare professionals.^18-20
  Information from randomized, controlled clinical trials and their systematic evaluation by meta-analysis and other techniques is based, at least in part, on scientific evidence. For example, the use of artificial skin grafts to promote wound closure in patients with chronic diabetic foot ulcers is grounded in firm Level 1 evidence,²¹ as is the use of moist wound management to improve healing.²² Curative use of dressings — eg, four-layer bandages to treat venous leg ulcers — provide other examples of prescribing based on Level 1 evidence.²³
  Failure to base therapeutic decisions on good evidence may deprive patients of a chance to benefit and will waste resources, limiting what can be spent on other aspects of health.⁷ Interdisciplinary working groups have been formed to develop best-practice recommendations relevant to wound care^24-26; these working groups use rigorous processes to develop guidelines based on the strongest evidence, which includes reviewing existing wound care recommendations and research literature, such as Cochrane reviews, and consulting national and/or international interprofessional consensus panels.^24-29
  The popularity of many old remedies derived, in part, from spontaneous resolution of wounds following their use.