Background: There were many existing studies on the overall quality of KOA CPGs, evidence quality and content analysis of recommendations. However, there is still lacking of methodological studies on the factors of the formation of recommendations that influence expert judgment. This study systematically surveyed KOA CPGs, and comprehensively summarized the influencing factors considered by their recommendations, and critically appraised the correspondence between the certainty of evidence and strength of recommendations, as well as an unambiguous interpretation of recommendations.
Objectives: To systematically evaluate the use of the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approaches and factors influencing the formation from evidence to recommendations in the knee osteoarthritis (KOA) related clinical practice guidelines (CPGs).
Methods: This is a methodological study. We searched PubMed, Embase, China National Knowledge Infrastructure, VIP Database for Chinese Technical Periodicals, Wanfang, and Chinese Biomedical Literature Database from 1 Jan. 2017 to 4 Dec. 2022. We included the most recent version of guidelines. We excluded guidelines for repeated publication and guidelines that described the methodology followed in the development of CPGs. Two reviewers, working independently, screened, extracted, and analyzed the evidence to the recommendation factor characteristics in the KOA CPGs.
Results: 39 eligible KOA CPGs with 767 recommendations were included (Figure 1 and Table 1). KOA CPGs mainly considering of desirable anticipated effects (706, 92.0%), undesirable anticipated effects (706, 92.0%), balance between desirable and undesirable effects (706, 92.0%) and certainty of the evidence (686, 89.4%) influence on the recommendations, the consideration of the other factors was less than 40% (Table 2). We identified 188(38.1%) strong recommendations, and only 42 (22.3%) and 57 (30.3%) were supported by high-certainty or moderate-certainty evidence. Conditional recommendations with high, moderate, low and very low certainty of evidence accounting for 79 (25.8%), 35(11.4%), 84 (27.5%), and 108 (35.3%) respectively. We identified 81 (15.8%) inappropriate recommendations(Table 3).
Conclusions: KOA CPGs lack application of the GRADE approaches. In the future, more attention should be paid to the research and improvement of methodology of recommendation formation.
Patient, public and/or healthcare consumer involvement: Owing to the nature of this work, no patient involved.

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