Longitudinal Patterns of Renal Function in Antineutrophil Cytoplasmic Antibody–Associated Vasculitis

Abstract

ObjectiveA 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.MethodsPatients 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.ResultsIn 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 m2) 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).ConclusionWe 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.image