FP101
PRESENTATION AND OUTCOMES OF ANCA ASSOCIATED VASCULITIS: THE SCOTTISH EXPERIENCE

INTRODUCTION AND AIMS: This is a national project undertaken on behalf of the Scottish Renal Biopsy Registry describing the presentation, biopsy appearances, management and outcomes of patients presenting with a new diagnosis of renal biopsy proven ANCA associated vasculitis (AAV) to all units in Scotland.

METHODS: The Scottish Renal Biopsy Registry collects data annually on all renal biopsies performed across Scotland. From the Registry, all patients with a possible diagnosis of AAV found on renal biopsy performed between1/1/2014 and 31/12/2015 were identified. Individual units searched the electronic patient records of each patient and identified all those with a new diagnosis of AAV. Those undergoing repeat biopsy or who were not felt to have AAV on biopsy were excluded. Demographic data including immunological and outcome data were recorded and statistical analysis was undertaken in SPSS (v22).

RESULTS: 105 patients were identified as having AAV across 8 centres and followed up for an average of 804 (IQR 610-1047) days. 57% (n=45) were referred via another medical specialty. In 50% (n= 53) the biopsy indication was acute kidney injury. 40% (n=42) had a diagnosis of granulomatosis with polyangiitis (GPA). 53% (n=56) were female and the mean age at biopsy was 65.1±10.8 years. 56% (n=59) were MPO positive. The average number of glomeruli on biopsy was 14 (IQR 11-21) with 3 (IQR 2-7) crescents. 28% (IQR 7-51) of viable glomeruli contained crescents. 35% (n=37) had at least 10% interstitial fibrosis on biopsy. The average duration of symptoms prior to diagnosis was 2 (IQR 1-3.8) months. Creatinine at biopsy was 217µmol/L (IQR 152-352 µmol/L) and at 90 days 146 µmol/L (IQR 105-224 µmol/L). Most patients received standard induction therapy of cyclophosphamide and steroid. 24% (n=25) had plasma exchange (PEX) at presentation and 14% (n=15) renal replacement therapy (RRT). 20% (n=21) patients relapsed with an average time to relapse of 873 (IQR 663-1065) days. 57% (n=12) of relapses were treated with rituximab. Those with GPA relapsed earlier ( 912 ( IQR 762-1063) ‘v’ 1183 (1109-1257) days, p= 0.02). 14% (n= 15) developed end stage renal disease (ESRD). 18% (n=19) died with 10 patients (9.5%) dying within 90 days of biopsy. Average time to death was 96 (IQR 59-217) days. There was a trend towards an increased risk of death with those who developed ESRD. Patients who received PEX or RRT during initial admission were no more likely to relapse or die than those who did not.

CONCLUSIONS: This study accurately describes the presentation, management and outcomes of patients with AAV and renal involvement in Scotland. This allows comparison between centres within Scotland and other countries. PEX and/or RRT at presentation did not confer increased risk of relapse nor of death which is reassuring. These descriptive data can help to inform both clinicians and patients. The small numbers are a limitation but the cohort will added to and reviewed annually to look at longer term outcomes.