Pathways to renal biopsy and diagnosis among patients with ANCA small-vessel vasculitis

Objectives. Antineutrophil cytoplasmic antibody small-vessel vasculitis (ANCA-SW) is an autoimmune systemic process increasingly recognised since the advent of antibody testing for the disease. Prompt diagnosis and institution of immunosuppressive therapy has been shown to improve patient outcome. The goal of this study was to better understand how patients navigate the health care system from symptom presentation to biopsy diagnosis, and to study the effects of prompt versus delayed diagnosis. Methods. Disease symptoms and number of physicians seen prior to renal biopsy were assessed for 127 ANCA-SW patients. Direct, delayed, and quest pathways to diagnosis and treatment of vasculitis were defined for both patients and providers. Kruskal-Wallis and Fisher exact tests were used to evaluate continual measures and compare categorical variables across pathways. Results. Among patients who sought direct care, physician delay in referral to a nephrologist was common (49/127, 71%, p=0.0023). Patients who delayed seeking care also experienced a delayed diagnosis 57% of the time (p=0.0023). Patients presenting with prodromal flu or upper respiratory involvement were more likely to have a delay/quest patient pathway (56% and 55%, respectively) than a direct patient pathway (44%, p=0.033 and 45%, p=0.019, respectively). There was a trend for patients with more severe loss of renal function to have a more direct referral to a nephrologist. Conclusion. Delay in diagnosis of ANCA SW may be due to lack of or non-specific symptoms, especially in patients who present with non-renal manifestations of disease. Better algorithms are needed to identify extra-renal manifestations, expedite diagnosis and improve patient outcomes.