# Clinical, laboratory, and histopathological characteristics of pediatric lupus nephritis: a retrospective study in a national referral center in Mexico

## TL;DR

This study examines the characteristics and risk factors of pediatric lupus nephritis in Mexico, identifying hypoalbuminemia as a key predictor of severe outcomes.

## Contribution

The study provides insights into pediatric lupus nephritis in a Latin American population and identifies hypoalbuminemia as a novel biomarker for severe outcomes.

## Key findings

- Proliferative histological forms of lupus nephritis are linked to higher inflammation and worse kidney function at diagnosis.
- Hypoalbuminemia is independently associated with the need for renal replacement therapy.
- The study includes one of the largest pediatric lupus nephritis cohorts from Mexico.

## Abstract

Pediatric lupus nephritis (LN) remains a major cause of morbidity and mortality, yet data from Latin American populations are limited. This study aimed to describe the clinical, laboratory, and histopathological characteristics of pediatric LN and identify prognostic factors associated with renal replacement therapy (RRT).

We conducted a retrospective cross-sectional study including patients <18 years of age with LN diagnosed between 2020 and 2024 at a national referral center in Mexico. Demographic, clinical, immunological, histopathological, and therapeutic variables at diagnosis were analyzed. Multivariable logistic regression was performed to identify predictors of RRT.

Eighty patients were included (83% female; mean age 15.1 ± 2.8 years). Median proteinuria was 41 mg/m²/h; hematuria and leukocyturia were present in 46% and 26% of patients, respectively. All patients were ANA positive, with frequent hypocomplementemia and elevated anti–double-stranded DNA titers. Among biopsied patients, class IV was the most common histological subtype (60%). Proliferative forms were associated with reduced glomerular filtration rate (<90 mL/min/1.73 m²; p = 0.012) and higher activity index scores (p = 0.04), while chronicity indices were low. Fifteen patients (18.8%) required RRT, and mortality was 6.25%. In multivariable analysis, hypoalbuminemia (<2.5 g/dL) was independently associated with RRT (OR 6.04; 95% CI 1.33–27.50; p = 0.020).

This study represents one of the largest pediatric LN cohorts reported from Mexico. Proliferative forms were associated with greater inflammatory activity and impaired renal function at diagnosis. Hypoalbuminemia emerged as a simple and accessible biomarker for early risk stratification of severe renal outcomes.