Longitudinal Patterns of Renal Function in Antineutrophil Cytoplasmic Antibody-Associated Vasculitis.

Objective: A spectrum of chronic kidney disease (CKD) and end-stage renal disease (ESRD) may occur in antineutrophil cytoplasmic antibody-associated vasculitis (AAV). The longitudinal trajectory of renal function in AAV is poorly understood.

Methods: Patients with ≥2 creatinine measurements, including at baseline (±30 days of treatment initiation), were included from the Mass General Brigham AAV Cohort. We calculated estimated glomerular filtration rate (eGFR). We incorporated longitudinal changes in eGFR into a group-based trajectory model to identify patients with similar patterns of change in renal function. The chi-square test and the Kruskal-Wallis test were used to evaluate differences between groups in categorical variables and non-normally distributed continuous variables, respectively.

Results: In 255 AAV patients, we identified 4 renal trajectory groups: rapid decline (n = 20), impaired (n = 82), preserved (n = 129), and recovery (n = 24). The rapid decline and impaired groups had greater baseline comorbidity (P = 0.01) and lower prevasculitis eGFR (P = 0.02). Clinically significant CKD (eGFR <60 ml/minute/1.73 m ) persisted over 5 years in >75% of the impaired group, compared to <40% of patients in the preserved group (P < 0.001). ESRD occurred most frequently in the rapid decline (100%), followed by the impaired and preserved groups (7% each). Baseline AAV renal involvement was present prior to 95% of ESRD. However, ESRD etiology varied, with 90% of rapid-onset ESRD attributed to vasculitis, versus 17-44% in impaired or preserved groups (P = 0.001).

Conclusion: We identified 4 longitudinal patterns of renal function after AAV diagnosis. Our findings highlight the burden of CKD in AAV and provide a framework for future research into personalized care in this vulnerable population.