Kidney Week

Abstract: FR-PO0679

Association Between Kidney Biopsy Activity and Chronicity Indices with Kidney Function and Proteinuria in Patients with Lupus Nephritis: A Cross-Sectional Analysis

Session Information

• Glomerular Diseases: Clinical, Outcomes, and Therapeutics Research - ANCA/FSGS
  October 23, 2026 | Location: Exhibit Hall A, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Glomerular Diseases

• 1402 Glomerular Diseases: Clinical, Outcomes, and Therapeutics

Authors

• Mora Loján, José Luis, Dr. Manuel Gea González General Hospital, Ciudad de Mexico, Mexico

José Luis Mora Loján, MD

• Romero Badillo, Mónica Lizbeth, Dr. Manuel Gea González General Hospital, Ciudad de Mexico, Mexico

Mónica Lizbeth Romero Badillo, MD

• Morton Martínez, Mirna, Dr. Manuel Gea González General Hospital, Ciudad de Mexico, Mexico

Mirna Morton Martínez

• Vélez Hurtado, Grecia, Dr. Manuel Gea González General Hospital, Ciudad de Mexico, Mexico

Grecia Vélez Hurtado, MD

• Juarez, Joana Balderas, Dr. Manuel Gea González General Hospital, Ciudad de Mexico, Mexico

Joana Balderas Juarez, MD

• Salinas-Ramirez, Mauricio Adrian, Dr. Manuel Gea González General Hospital, Ciudad de Mexico, Mexico

Mauricio Adrian Salinas-Ramirez, MD

• Hernández Castillo, José Luis, Dr. Manuel Gea González General Hospital, Ciudad de Mexico, Mexico

José Luis Hernández Castillo, MD

• Cruz, Nestor Humberto, Dr. Manuel Gea González General Hospital, Ciudad de Mexico, Mexico

Nestor Humberto Cruz, MD

Background

Lupus nephritis (LN) is one of the most severe manifestations of systemic lupus erythematosus and is one of the most frequent causes of chronic kidney disease. The activity (AI) and chronicity (CI) indices reported guide therapeutic management; however, their independent contribution to renal function and proteinuria has not yet been fully characterized. This study aims to evaluate the association of histological indices with the clinical variables.

Methods

This was a cross-sectional, analytical, observational study that included 23 patients with lupus nephritis (LN) confirmed by kidney biopsy, evaluated at the Dr. Manuel Gea González General Hospital between 2017 - 2026. The variables analyzed included estimated glomerular filtration rate (CKD-EPI), continuous 24-hour proteinuria analyzed in two subgroups (<3.5 g/24h and ≥3.5 g/24h), activity and chronicity, according to the modified NIH score. Variables with a non-normal distribution were analyzed using Spearman correlation, Mann-Whitney U test, and linear regression on ln(eGFR) plus verification of assumptions (Durbin-Watson, VIF, Cook distance).

Results

The reported population included 96% women with a median age of 27 years, presenting a median eGFR of 38 mL/min/1.73 m² (IQR 117), 24-hour proteinuria of 1524 mg (IQR 2140). eGFR correlated inversely with AI (rho = −0.445; p = 0.034); the other bivariate correlations were not significant. Dichotomization of proteinuria (19 vs. 4 pts) showed no differences between groups (p > 0.20). Simple regression applied to ln(eGFR) was not significant (β = −0.327; p = 0.128; R² = 0.107). Similarly, the multivariable model applied (n = 23) was not significant (adjusted R² = 0.049; p = 0.234). After the variable adjustements, the model reached statistical significance (adjusted R² = 0.278; F = 5.044; p = 0.017), where each additional point of AI independently predicted an approximate 7.7% reduction in eGFR (β = −0.603; B = −0.080; 95% CI −0.134 to −0.027; p = 0.005).

Conclusion

In this NL cohort, the histological activity index was an independent predictor of eGFR after adjusting for chronicity. Each additional point on the AI corresponded to approximately a 7.7% decrease in eGFR. These findings support the clinical relevance of the histological activity score and warrant its validation in larger cohorts.