Evidence and guidelines in otorhinolaryngology: the merits of evidence-based case reports

Abstract

Evidence-based medicine refers to the conscientious, explicit and judicious use of the current best evidence to support decision making at point of care. To facilitate the transition of evidence into daily practice several evidence-based otorhinolaryngology guidelines have been developed. In this thesis we first describe a survey among Dutch otorhinolaryngologists to study their current awareness, knowledge, and opinion of these evidence based guidelines since clinical uptake of guidelines is of high importance. Our results show that Dutch otorhinolaryngologists are familiar with the available guidelines and a majority uses them in daily practice. Most choose treatment consistent with the guideline. The lack of strict recommendations in guidelines can be difficult to use directive, but it also gives room for flexibility and preferences of doctors and patients when selecting treatment.

Since guidelines have such a prominent role in clinical practice, it is important that recommendations in these guidelines are formulated in the same systematic and transparent way, based on the best available evidence. If different guidelines are substantiated from similar scientific studies, they will generate similar conclusions and corresponding recommendations. However, in a comparative study between English (SIGN) Dutch (CBO) and American (ICSI) guidelines for the diagnosis and treatment of patients with obstructive sleep apnea syndrome (OSAS), we come to the conclusion that these guidelines focus on different aspects of the management of OSAHS. Furthermore, for similar clinical questions these 3 guidelines showed conflicting conclusions (11%-18%), differences in attached levels of evidence (32%-63%), and remarkable discrepancies in cited studies. A plausible explanation for these differences is the citation preference for papers from members of the guideline work group and from own country. Despite different publication dates, more recent guidelines fail to cite earlier published guidelines. Despite the generally accepted approach regarding the development of Evidence Based guidelines, remarkable differences exist between guidelines from different countries on the same clinical subject.

At last, we emphasize the potential additive value of Evidence Based Case Reports (EBCR’s) to earlier reported limitations of the current evidence based guideline development. An EBCR starts with a knowledge gap identified in daily practice regarding diagnosis, prognosis, or interventions. An explicit and transparent approach is followed, and practical best evidence summaries are provided that are applicable to specific patient management issues. EBCR’s may play a role in guideline development since evidence is transparently separated from judgement. EBCR’s can be used to assist guideline panel consensus sessions. An apparent definition of knowledge gaps and a formal system for rating the evidence can be used. Subsequently, recommendations can be progressively formed by the guideline panel using a considered judgement approach during a group decision making process, instead of being based on so-called “expert discussion”. Furthermore, EBCR’s can also be used in the formation or adjustment of local diagnostic and treatment protocols, and assist in developing interactive media, to further improve evidence and guidelines in otorhinolaryngology