Role of lupus nephritis classification systems in everyday clinical practice: a questionnaire-based survey of the Renal Pathology Society (RPS)

Background Kidney biopsy is the gold standard for lupus nephritis (LN) diagnosis, with the 2018 International Society of Nephrology/Renal Pathology Society (ISN/RPS) histopathological classification widely used for prognosis and treatment decisions. A survey assessing the use of the 2018 ISN/RPS classification in daily practice was recently conducted on behalf of the RPS. Methods An online survey was sent to active RPS members after a webinar which introduced RPS members to the topic. The survey contained multiple-choice and open-ended questions and remained open 30 days for completion. Results were analyzed anonymously. Results Of 562 RPS members, 185 (32.9%) replied to the questionnaire; 180 (97.8%) were pathologists and 120 of these (64.8%) indicated they encounter more than 20 biopsies with LN per year. The 2018 ISN/RPS classification and the modified NIH activity/chronicity indices are used by 92.4% and 88.1% of respondents, respectively. Respondents rated the utility of both systems with a median score of 8 (IQR 7-9) on a 1-10 scale. Suggested improvements to the current classification system include greater standardization and simplicity, clearer definitions for gray-zone entities, and the introduction of guidelines for new parameters and biomarkers. Conclusions This study shows that the 2018 ISN/RPS LN classification is widely used in everyday practice by pathologists. Our results highlight the need for ongoing refinement to facilitate targeted treatment decisions, particularly considering evolving phenotypes and therapeutic advancements in LN.