What does expert opinion in guidelines mean? a meta-epidemiological study.

Area of Science:

• Medical Guidelines
• Evidence-Based Medicine
• Health Research

Background:

• Guidelines frequently use "expert opinion" (EO) to qualify recommendations.
• The basis and evidence type for these EO recommendations are often unclear.

Purpose of the Study:

• To investigate the rationale and evidence types underpinning "expert opinion" (EO) recommendations in contemporary medical guidelines.
• To assess the transparency and quality of evidence used when EO is cited.

Main Methods:

• Systematic search of multiple databases and websites for guidelines published in the last decade that utilized the term "expert opinion" (EO).
• Analysis of included guidelines to identify the number of recommendations qualified as EO and the stated rationale or evidence type.
• Categorization of evidence types cited for EO recommendations, including direct vs. extrapolated evidence and study designs.

Main Results:

• Of 69 included guidelines, 907 of 2390 recommendations were qualified as EO.
• A rationale for using the EO designation was absent in 91% of cases.
• The most common evidence cited was extrapolated from studies not directly addressing the guideline question (e.g., 40% from randomized trials, 38% from observational studies).
• Only 5.6% of EO recommendations could have been classified as good practice statements, and none were solely based on panel experience.

Conclusions:

• The use of "expert opinion" (EO) as a level of evidence in guidelines persists but often lacks explicit justification.
• Evidence labeled as EO is frequently indirect or of low quality, such as case series.
• Explicitly describing the evidence type, rather than using the "expert opinion" (EO) label, could enhance recommendation clarity, transparency, and adoption.