The diagnostic pathway and time to diagnosis in ANCA-associated vasculitis: a retrospective study at a tertiary rheumatology center

OBJECTIVE: To analyze the diagnostic pathway of patients with ANCA-associated vasculitis (AAV) and to identify factors associated with the time to diagnosis, including the role of referring and previously consulted medical specialties. METHODS: This retrospective single-center study analyzed patients with granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), and eosinophilic granulomatosis with polyangiitis (EGPA) who received their diagnosis between 2014 and 2024. Data were extracted from medical records. Time to diagnosis was defined as the period between first AAV-related symptoms and confirmed diagnosis. Factors associated with diagnostic delay were analyzed using multivariate Cox regression. Temporal differences between subtypes were visualized using Kaplan-Meier curves. RESULTS: A total of 216 patients were included (GPA n = 128; MPA n = 70; EGPA n = 18). Median time to diagnosis was numerically longest in EGPA (455 days [IQR 144-924]) compared with GPA (120 days [IQR 61334]) and MPA (153 days [IQR 90-366]). Renal involvement was statistically associated with a shorter time to diagnosis (HR 1.65, 95% CI 1.18-2.31, p = 0.004), whereas prior consultations with dermatologists (HR 0.41, p = 0.004), pulmonologists (HR 0.58, p = 0.003), and rheumatologists (HR 0.63, p = 0.003) showed longer delays. Higher BVAS and CRP levels statistically correlated with shorter diagnostic intervals. CONCLUSION: The diagnostic delay in AAV varies by disease subtype and clinical presentation. EGPA shows the numerically longest time to diagnosis, while renal involvement seems to facilitate earlier diagnosis. Enhanced awareness among non is essential to reduce diagnostic delay and prevent organ damage, although outcome measures were not assessed in our study. Key Points • Diagnostic delay in ANCA-associated vasculitis varies between disease subtypes, organ involvement, and consulted specialties. • EGPA shows the numerically longest diagnostic delay, whereas renal involvement seems to facilitate earlier diagnosis. • Earlier recognition of AAV across specialties may reduce diagnostic delay and prevent organ damage.