Level of scientific evidence underlying recommendations arising from the American Urological Association and European Urological Association guidelines on stone disease.

purposeThe purpose of this study was to systematically evaluate the quality and characteristics of the evidence base, including the levels of evidence (LOE) and grades of recommendation (GOR), underpinning the clinical practice guidelines for stone disease by the American Urological Association (AUA) and the European Association of Urology (EAU).

methodsWe analyzed the AUA clinical and surgical guidelines (2016 and 2019) and the EAU guideline (2020) for stone disease. We categorized these studies by type, country of origin, publication year, and journal impact factor. Each study was classified based on its design and assigned a level of evidence using the Oxford Centre for Evidence-based Medicine criteria. We also assessed the grade of recommendation. Correlations between study characteristics and levels of evidence were analyzed.

resultsThe EAU guideline referenced 599 studies, the AUA medical guideline 156 studies, and the AUA surgical guideline cited 235 studies. The studies predominantly originated from the USA, with notable contributions from European countries. Systematic reviews and randomized controlled trials were the most common study types across all guidelines. However, a large proportion of studies were classified at lower evidence levels, with Level 2B studies representing the majority. High-quality studies (Levels 1 to 2 A) made up 47.2% of the EAU guideline, 38.5% of the AUA medical guideline, and 38.7% of the AUA surgical guideline. Grade A recommendations were assigned to 34-40% of studies, with the EAU guideline showing a slightly higher percentage of high-quality recommendations. Correlation analysis revealed weak but significant relationships between study quality and parameters such as year of publication, number of subjects, and journal impact factor in the EAU guideline.

conclusionThis study highlights significant variability in the levels of evidence and grades of recommendation between the AUA and EAU guidelines for stone disease. The predominance of lower-tier evidence (Level 2B) across both guidelines underscores a potential gap in high-quality, large-scale randomized controlled trials in stone disease. Future guideline development could benefit from adopting more rigorous methodologies to reduce subjectivity and enhance the transparency of evidence synthesis.