Routine antinuclear antibody testing as an independent prognostic biomarker for end-stage renal disease in ANCA-associated vasculitis: a longitudinal cohort study.

INTRODUCTION

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) frequently involves the kidney. Although a subset of AAV patients tests positive for serum antinuclear antibody (ANA), data on the association between ANA positivity and progression to end-stage renal disease (ESRD) in AAV remain limited.

METHODS

This retrospective cohort study enrolled 236 patients with AAV. Patients were categorized according to ANA status. Baseline clinical, laboratory, and renal histopathological parameters were analyzed. The primary endpoint was progression to ESRD, assessed using Kaplan-Meier and Cox analyses. Risk stratification was performed based on ANA status and baseline estimated glomerular filtration rate (eGFR).

RESULTS

Serum ANA positivity was observed in 37.3% of patients. Patients with positive ANA had worse baseline renal function and more prominent IgG deposition on renal pathology. The cumulative incidence of ESRD was significantly higher in the ANA-positive group during follow-up. Multivariable Cox regression confirmed ANA positivity as an independent risk factor for ESRD after adjusting for baseline eGFR and age. Risk stratification combining ANA status and eGFR (<30 mL/min/1.73m2) identified a high-risk subgroup with a 7.19-fold increased ESRD risk. In sensitivity analyses, ANA positivity remained significantly associated with ESRD after additional adjustment for proteinuria, disease activity, ANCA specificity, or treatment.

CONCLUSION

Routine serum ANA testing provides valuable prognostic information for predicting progression to ESRD in AAV patients. The combination of ANA positivity and reduced eGFR offers a simple and clinically actionable risk stratification model. These findings support the integration of ANA status into routine clinical risk assessment for AAV, providing a simple and actionable tool for the early identification of high-risk patients requiring intensified monitoring.