Background and objectives: The overlap between antineutrophil cytoplasmic antibody (ANCA) associated glomerulonephritis (ANCA-GN) and connective tissue diseases (CTD) has been reported mainly as case series in the literature. Frequency of this association, as well as presentation and outcomes are unknown.
Materials and methods: Patients from the Maine-Anjou ANCA-associated vasculitides (AAV) registry with ANCA-GN diagnosed between 01/01/2000 and 01/01/2018, ANCA positivity, and at least six months of follow-up, were included.
Results: 106 out of 142 patients fulfilled the inclusion criteria and were analyzed. CTD was present at ANCA-GN diagnosis in 16 (15.1%) patients. The most common CTD were rheumatoid arthritis, Sjogren syndrome and systemic sclerosis. Compared to the control group, females were more represented in the CTD group (75%, p = 0.001). Renal presentation was comparable between groups, including the pathological analysis of renal biopsies. Patients of CTD group presented a higher rate of non-renal relapse (25% versus 7.7%, p = 0.037), and experienced more frequently a venous thrombotic event (31.2% versus 10%, p = 0.021). No difference between groups was observed according to major outcomes.
Conclusion: Association between CTD and ANCA-GN is not a rare condition and predominantly affects females. While AAV presentation is not significantly different, CTD patients experience more frequently non-renal relapse and venous thrombotic events.
Keywords: ANCA; connective tissue disease; glomerulonephritis; vasculitis.