Association Between Any Circulating ANCA Positivity at Diagnosis and Subsequent End-Stage Kidney Disease in Microscopic Polyangiitis and Granulomatosis with Polyangiitis

Background and Objectives: This study examined whether positivity for any antineutrophil cytoplasmic antibody (ANCA) at diagnosis was associated with subsequent advanced systemic complications during follow-up in patients with microscopic polyangiitis (MPA) and granulomatosis with polyangiitis (GPA). Materials and Methods: We retrospectively reviewed the medical records of 271 patients with MPA or GPA enrolled in the ANCA-associated vasculitis cohort at a tertiary hospital. Any ANCA positivity was defined as the presence of any of the following: myeloperoxidase-ANCA, proteinase 3-ANCA, perinuclear ANCA, or cytoplasmic ANCA. Subsequent advanced systemic complications during follow-up, such as all-cause mortality and end-stage kidney disease (ESKD), were evaluated. Results: The median age of the 271 patients with MPA or GPA was 62.0 years, and 239 and 32 were identified as ANCA-positive and ANCA-negative vasculitis, respectively. During follow-up, 47 patients (17.3%) died, and 52 (19.2%) progressed to ESKD. In a cross-sectional comparative analysis, ESKD occurred significantly more frequently in ANCA-positive patients than in ANCA-negative patients. Among the five subsequent advanced systemic complications of MPA and GPA, ANCA-negative patients exhibited a significantly higher cumulative ESKD-free survival rate than ANCA-positive patients. However, in multivariable Cox proportional hazards analysis adjusted for age, sex, AAV subtype, and baseline serum creatinine, ANCA positivity was not independently associated with subsequent ESKD. Conclusions: Any ANCA positivity at diagnosis was associated with subsequent ESKD in unadjusted analyses but was not an independent predictor after adjustment for baseline renal function and other clinically relevant covariates.