Low-Grade Proteinuria Does Not Predict Favorable Outcomes in Lupus Nephritis: A Longitudinal Cohort Study

Area of Science:

• Nephrology
• Immunology
• Rheumatology

Background:

• Lupus nephritis (LN) is a severe complication of systemic lupus erythematosus.
• Proteinuria is a key marker for assessing LN activity and prognosis.
• Understanding the impact of baseline proteinuria levels on LN outcomes is crucial for patient management.

Purpose of the Study:

• To evaluate clinical characteristics, renal pathology, treatment responses, and renal outcomes in LN patients stratified by baseline proteinuria levels.
• To determine if lower baseline proteinuria (<1g/24h) is associated with improved outcomes compared to higher levels (≥1g/24h).
• To identify predictors of long-term renal function decline in incident and relapsing LN.

Main Methods:

• Retrospective analysis of 239 biopsy-proven LN patients.
• Stratification based on baseline proteinuria (<1g/24h vs. ≥1g/24h) and disease onset (incident vs. relapsing).
• Assessment of treatment response and renal outcomes using established criteria; Cox regression and Kaplan-Meier analyses for survival outcomes.

Main Results:

• Patients with low-grade proteinuria (<1g/24h) showed similar treatment response rates and long-term renal outcome risks (eGFR decline) compared to those with high-grade proteinuria (≥1g/24h).
• Low-grade proteinuria was associated with less active renal pathology but similar chronicity.
• Glomerulosclerosis independently predicted long-term renal deterioration in relapsing LN, but not in incident LN.

Conclusions:

• Baseline proteinuria level alone is not a reliable indicator of renal outcomes or treatment response in LN.
• Glomerulosclerosis is a significant predictor of renal function decline in relapsing LN, highlighting the need for targeted therapies.
• Emphasizes the importance of early renal biopsy, personalized treatment strategies, and close monitoring for effective LN management.