Supplementary Material for: Transparency of Systematic Reviews on Interventions for Multiple Sclerosis: Adherence to the GRADE Approach. Meta-research.

Introduction: Many systematic reviews summarize research on interventions for multiple sclerosis (MS), yet concerns persist about their methodological quality. Assessing the certainty of evidence is a crucial step to ensure transparency and reliability in decision-making. The Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach is a widely accepted framework for this purpose; however, its application in MS systematic reviews remains unclear. Methods: A comprehensive search was conducted across the MEDLINE, Cochrane Database of Systematic Reviews, and Epistemonikos databases. The included reviews were assessed for their use of GRADE and the Summary of Findings (SoF) table. Results: We assessed 276 systematic reviews and observed a growing trend in publication over the past decade. Only 15% (42/276) applied the GRADE approach, of which 83% included a SoF table with explanations for evidence downgrades. Half of these were Cochrane reviews, where a SoF table is mandatory. Conclusion: This meta-research study highlights gaps in methodological rigor in systematic reviews of MS. Strengthening adherence to best practices in evidence synthesis, particularly systematic certainty assessments using the GRADE approach, is essential for improving the reliability of recommendations and supporting evidence-based decision-making in MS care.