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

## TL;DR

This survey shows how kidney pathologists use the 2018 lupus nephritis classification system and highlights areas for improvement in diagnosis and treatment guidance.

## Contribution

The study provides insights into real-world use of the 2018 ISN/RPS classification and identifies needed refinements for better clinical application.

## Key findings

- 92.4% of pathologists use the 2018 ISN/RPS classification for lupus nephritis.
- Respondents suggest improvements like standardization and clearer definitions for ambiguous cases.
- The modified NIH activity/chronicity indices are used by 88.1% of respondents.

## Abstract

Kidney biopsy is the gold standard for lupus nephritis (LN) diagnosis, with the 2018 International Society of Nephrology (ISN)/Renal Pathology Society (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.

An online survey was sent to active RPS members after a webinar that introduced RPS members to the topic. The survey contained multiple choice and open-ended questions and remained open 30 days for completion. Results were analysed anonymously.

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 >20 biopsies with LN per year. The 2018 ISN/RPS classification and the modified National Institutes of Health 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 (interquartile range 7–9) on a 1–10 scale. Suggested improvements to the current classification system include greater standardization and simplicity, clearer definitions for grey-zone entities and the introduction of guidelines for new parameters and biomarkers.

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.

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