Trends in category and grade for therapeutic plasma exchange in the latest guideline on therapeutic apheresis by the American Society for Apheresis: Hurdles in pursuing evidence-based medicine

Background and ObjectivesThe Writing Committee of American Society for Apheresis released the ninth edition of guidelines for therapeutic apheresis in 2023. Categories have been a part of the guidelines since the first edition, and the grading system was introduced in the fifth edition, with updates in every new edition. In this study, we investigated the category and grade change trends through the latest five editions, focusing on therapeutic plasma exchange, to suggest future directions as part of evidence-based medicine.Materials and MethodsCategories and grades for therapeutic plasma exchange (TPE) were collected and analysed from the fifth through ninth editions. We aligned classification changes to the ninth edition's clinical context and compared its categories and grades with those introduced in the guideline.ResultsAmong 166 total indications in the ninth edition, 118 included TPE procedure, either as a sole treatment or as one of the therapeutic apheresis techniques. The total number of indications changed, but Category III remained predominant throughout the editions. Similarly, Grade 2C consistently emerged as the most prevalent grade. Notably, 24 cases had grade changes. Of the 16 cases with evidence quality changes, the quality weakened in six and improved in 10. Evidence levels were not improved throughout the study period for 102 clinical conditions.ConclusionTo address gaps in evidence quality, international collaboration is imperative to establish comprehensive large-scale studies or randomized controlled trials. This will refine the use of therapeutic apheresis, including TPE, to foster evidence-based advancements in clinical practice.