Results
A total of 121 patients met the inclusion criteria; Eighteen patients were excluded because of insufficient clinical information (n=9), early death (n=5), vasculitis limited to the skin (n=4), non-classifiable vasculitis (n=2) or vasculitis associated with cocaine abuse (n=2). Thus, 99 patients were finally included in the analyses.
Table 1 summarises the clinical characteristics of the patients included in the study. Patients’ mean age at diagnosis was 56.5 years and median follow-up was 9 years. Overall, 55 patients were diagnosed with MPA, 36 with GPA, and 8 with EGPA. Out of 99 patients, 67 (68%) were positive for anti-MPO antibodies and 32 (32%) for anti-PR3 antibodies.
All but one of the patients with anti-PR3 antibodies were diagnosed with GPA. Compared to patients with anti-MPO antibodies, those with anti-PR3 antibodies were younger and had a higher prevalence of purpura, arthritis, pulmonary infiltrates or nodules and eye-nose-throat (ENT) or ocular involvement. Patients with anti-PR3 antibodies had a higher rate of clinical relapses but lower mortality than patients with anti-MPO antibodies. Patients with anti-MPO antibodies were characterised by a higher prevalence of microhematuria, renal failure, and ESRD than patients with anti-PR3 antibodies (Table 1).
Time-course analysis of ANCA levels identified 26 (26.3%) patients with monophasic pattern; 13 patients (13.1%) with remitting pattern; 39 patients (39.4%) with recurrent pattern; and 21 patients (21.2%) with persistent ANCA pattern. Clinical characteristics, diagnosis, ANCA specificity, treatment administered and outcome according to ANCA patterns are shown in Table 2.
Patients with a monophasic o remitting ANCA pattern were more commonly diagnosed with MPA and had a higher prevalence of anti-MPO antibodies. These patients more often presented with ESRD at baseline and had received plasmapheresis more commonly than patients with a recurrent or persistent ANCA pattern (Table 2).