ANCA associated vasculitis in patients from Saudi Arabia

Objective: To explore clinical and laboratory features, therapy and outcome of antineutrophil cytoplasmic antibodies (ANCA) associated vasculitis (AAV) patients from our tertiary care center.

Methods: This study of AAV patients seen in Rheumatology clinics at King Khalid University hospital (KKUH), King Saud University, Riyadh during the period 1990-2014 was carried out retrospectively. Demographic, clinical, haematological and immunological parameters along with therapy, complications and outcome were retrieved from patients’ medical charts. Different characteristics were compared between the three groups of AAV; GPA (Granulomatosis with polyangiitis), MPA (Microscopic polyangiitis) and EGPA (Eosinophilic granulomatosis with polyangiitis).

Results: We identified 34 AAV patients (21 males: 13 females; 31 Saudis: 3 non-Saudis) comprising of 23 GPA, 2 MPA and 9 EGPA cases. The mean age of onset was 42.1±17.6 years (range 11-75) and mean duration of disease was 8.7± 5.1 years (range 1-20). The most frequently affected system was pulmonary in all AAV (73.5%), GPA (65.2%) and EGPA (100%) while it was renal in MPA (100%) patients. Ophthalmological and upper airways involvement was higher in GPA. Neurological involvement was higher in EGPA (p<0.05). ANCA were detected in 79.4% of AAV patients, of them c-ANCA were 77.8% and p-ANCA 22.2%. ANCA was positive in 91.3% GPA, 100% MPA and 44.4% EGPA patients. In GPA c-ANCA were detected in 80.9% and p-ANCA in 17.4%, in MPA, c-ANCA were detected in 50% and p-ANCA in 50% , in EGPA, c-ANCA were observed in 75% and p-ANCA in 25%. GPA patients had PR3 specificity in 93.3%, and MPO in 6.7%, PR3 was present in all MPA patients (100%), while EGPA patients had MPO (100%). Therapy administered were corticosteroids (100%), intravenous cyclophosphamide (58.8%), azathioprine (50%) and rituximab (11.8%). Infections were noted in 29.4%.

Conclusions: The 10-year survival in our AAV patients was 95%. ANCA pattern was similar to Caucasian AAV patients and different from Japanese and Chinese AAV patients.