Clinical practice guidelines for nephrotic syndrome: systematic assessment of their quality and the concordance between certainty of evidence levels and strength of recommendations

Clinical practice guidelines (CPGs) aim to provide appropriate clinical practice recommendations based on available evidence while acknowledging existing gaps and uncertainties. However, the quality of CPGs for nephrotic syndrome (NS) remains unknown, and the distribution of evidence certainty, as well as the strength of recommendations, is currently unclear. We systematically evaluated the quality of CPGs for NS to identify areas for improvement in their development processes. We searched PubMed, the Cochrane Library, Embase, the Cumulative Index to Nursing and Allied Health Literature, and six CPG-specific databases. The eligibility criteria included the latest versions of guidelines on nephrotic syndrome diagnosis and treatment, published in English between 2011 and 2024, excluding unavailable full text, translated/adapted versions, duplicates, or editorial-type articles. Three researchers independently assessed methodological quality using AGREE II, while consensus approaches evaluated reporting and recommendation quality with RIGHT and AGREE-REX. Using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system as a reference framework, we analyzed the distribution of evidence certainty and recommendation strength in evidence-based CPGs. Our systematic search identified 2,955 records, with 13 CPGs ultimately meeting the inclusion criteria. The assessed CPGs demonstrated a mean overall methodological quality score of 64.2% (41.7% − 78.4%), with seven classified as high quality. Regarding reporting quality, the average reporting rate was 69.3% (42.9% − 88.6%), with 10 CPGs rated as having moderate reporting quality, two with high reporting quality, and one with low reporting quality. The mean overall recommendation quality score was 49% (40.7% − 64.8%). Among the 435 extracted recommendations, 49.9% were graded as strong. The CPGs for NS demonstrate inconsistent overall quality, with uneven performance across different domains. Furthermore, there is poor concordance between recommendation strength and evidence certainty.