Kidney Week

Abstract: TH-PO0721

Proteinuria or Albuminuria for the Follow-Up of Patients with Lupus Nephritis?

Session Information

• Glomerular Innovations: Artificial Intelligence, Multiomics, and Biomarkers
  November 06, 2025 | Location: Exhibit Hall, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Glomerular Diseases

• 1402 Glomerular Diseases: Clinical, Outcomes, and Therapeutics

Authors

• Navarro Sanchez, Valeria, Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Mexico City, CDMX, Mexico

Valeria Navarro Sanchez, MD

• Rivero Otamendi, Emiliano, Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Mexico City, CDMX, Mexico

Emiliano Rivero Otamendi

• Hernández Andrade, Adriana, Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Mexico City, CDMX, Mexico

Adriana Hernández Andrade, MD

• Zavala Miranda, María Fernanda, Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Mexico City, CDMX, Mexico

María Fernanda Zavala Miranda

• Sánchez-Mejía, Daniela Edith, Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Mexico City, CDMX, Mexico

Daniela Edith Sánchez-Mejía

• Cruz Rivera, Cristino, Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Mexico City, CDMX, Mexico

Cristino Cruz Rivera

• Mejia-Vilet, Juan M., Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Mexico City, CDMX, Mexico

Juan M. Mejia-Vilet, MD, MS, MSc, PhD

Background

Albuminuria is used for the follow-up of CKD and DKD. In lupus nephritis, definitions of response are based on proteinuria or urine protein to creatinine ratio (uPCR). We aimed to evaluate the course of uACR and uPCR over the first year of follow-up of patients with LN.

Methods

We included 106 patients. All received immunosuppressive therapy and were followed quarterly for ≥36 months. uACR and uPCR were measured in spot samples at flare, 3, 6, and 12 months. Response was defined according with KDIGO. Stable eGFR was defined as an eGFR slope ≤1mL/min/1.73m². Correlation was assessed by linear regression. Predicted uACR was calculated from uPCR and agreement evaluated by intraclass correlation coefficient (ICC) and Bland-Altman plots. The course of uACR, uPCR, and their ratio was evaluated by linear mixed models for repeated measurements. The predictive value for stable kidney function of 12^th-month uPCR and uACR was determined by ROC curves.

Results

We included 106 patients, median age 31 years (IQR 25-38), 93 (88%) female. Creatinine was 0.9mg/dL (IQR 0.6-1.3), uPCR 3.0 g/g (IQR 1.9-5.3), uACR 1.9g/g (1.1-3.7). All patients were treated with glucocorticoids in combination with MMF, cyclophosphamide, or tacrolimus. After 12 months, 36 (34%), 27 (26%), 43 (41%) achieved a complete, partial or no response, respectively. uPCR and uACR were highly correlated at all study timepoints, with r²=0.946 and slope of 0.67 (95%CI 0.65-0.68) for the full cohort (Figure 1A). Agreement between predicted and observed uACR was excellent with ICC of 0.97 (95%CI 0.96-0.98) and P30 ≥80% at all timepoints. The uACR/uPCR ratio slightly decreased in all response groups from flare to the 12^th month timepoint but was not different among response groups (Figure 1B). The best cutoff for predicting stable eGFR over follow-up were 0.71g/g and 0.41g/g for uPCR and uACR, respectively.

Conclusion

Both uPCR and uACR may be used for the first year of follow-up of LN and are predictive of stable kidney function. uACR may be predicted from uPCR.

Digital Object Identifier (DOI)

• doi: 10.1681/ASN.20256qwtdzrn