Longitudinal Trajectories of Kidney Function in Patients with Severe Antineutrophil Cytoplasmic Antibody-Associated Vasculitis

Objective: ANCA-associated vasculitis (AAV) causes glomerulonephritis culminating in a spectrum of chronic (CKD) and end-stage kidney disease (ESKD). Kidney function trajectories with differing CKD risk were reported in a single-center study. We sought to confirm these findings in the Plasma Exchange and Glucocorticoids in Severe AAV (PEXIVAS) trial cohort. Methods: This cohort study included patients from PEXIVAS with a baseline and one or more estimated glomerular filtration rate (eGFR) measurements over 36 months to identify groups with similar longitudinal change in kidney function using group-based trajectory analysis. We evaluated factors associated with group membership using multivariable-adjusted multinomial logistic regression. Results: We identified four trajectory groups among 663 patients: Early ESKD (113, 17%); Stable Impairment (400, 60%); Impaired with Improvement (131, 20%); Marked Improvement (19, 3%). ESKD occurred in 137 patients (21%): 113 (100%) in the Early ESKD, 23 (6%) in the Stable Impairment, and one (1%) in the Impaired with Improvement groups. Older baseline age (aOR=0.97 per one year, 95%CI 0.95-0.99), female sex (aOR=0.54, 95%CI 0.31-0.94), and baseline eGFR (aOR=0.93 per 1 mL/min/1.73 m 2 increase, 95%CI 0.88-0.99) were associated with lower odds of Early ESKD vs Impaired with Improvement membership. MPO-ANCA+ (aOR=2.35, 95%CI 1.33-4.16) and hypertension (aOR=2.50, 95%CI 1.33-4.69) were associated with higher odds of Early ESKD membership. Conclusions: We identified four kidney function trajectories in AAV associated with varied risk of ESKD and CKD; male sex, MPO-ANCA specificity, baseline hypertension and lower baseline eGFR were associated with adverse kidney function trajectory. Differences in baseline characteristics identify potential targets for personalized care.