title: Quality and relevance of evidence in support of guideline recommendations for sleep laboratory investigations.
abstract: OBJECTIVE
  As part of a review of guidelines for sleep laboratories, this study summarizes the quality and relevance of evidence cited in support of recommendations on investigations for individuals with sleep disorders.
  
  
  METHODS
  Quality of evidence in support of each recommendation was rated as A (from well-conducted, prospective controlled studies), B (from controlled studies and case series, with minor shortcomings), or C (from case series or case series plus controlled studies with substantial limitations). Relevance of the cited evidence was also rated from A to C, in decreasing order of merit.
  
  
  RESULTS
  Of eighty-one recommendations from thirty-seven guidelines, forty-six were supported by evidence from primary studies. Six recommendations were supported by category A evidence, fifteen by category B, and twenty-five recommendations by category C. The cited evidence was highly relevant to eighteen recommendations, of some relevance for twenty-two and of little or no relevance to six. Four recommendations were informed by an absence of available evidence. For the other thirty-one, no evidence was provided in support.
  
  
  CONCLUSIONS
  The approach used provided a concise overview of recommendations and supporting evidence for decision-makers. Guidelines on the use of sleep laboratory investigations contain much detailed information, but evidence supporting several recommendations is of limited quality and relevance. Furthermore, good-quality studies of many sleep laboratory applications are needed to assist both health policy formulation and clinical practice.
authors.affiliation: Department of Public Health Sciences, University of Alberta, 13-130 Clinical Sciences Building, Edmonton, Alberta T6G 2G3, Canada. dhailey@ozemail.com.au
authors.forename: David
authors.initials: D
authors.lastname: Hailey
authors.forename: Khai
authors.initials: K
authors.lastname: Tran
mesh_terms: D000416:Alberta; D019317:Evidence-Based Medicine; D017408:Guidelines as Topic; D006801:Humans; D011446:Prospective Studies; D012107:Research Design; D012893:Sleep Wake Disorders / Q000175:diagnosis*