360. Outcomes in ANCA-associated vasculitis: validating a renal risk score and examining the impact of deprivation
Creators: name: Dominic McGovern1, 2
Publisher: name: Zenodo
Year: 2022
Subjects: Vasculitis
ANCA
Abstracts
Giant Cell Arthritis
MPA
GPA
EGPA
Takayasu
IgA vasculitis

description: <strong>Background/Objectives:</strong> Predicting outcomes in ANCA-associated vasculitis (AAV) can be challenging. Using our national cohort of patients who have had AAV confirmed on kidney biopsy, we aimed to validate an ANCA renal risk score (ARRS) which utilises histopathological and biochemical data to predict outcomes<sup>1</sup>. We then used the same cohort to answer an important epidemiological question - whether deprivation is associated with poorer outcomes in AAV. <strong>Methods:</strong> The Scottish Renal Biopsy Registry is a complete national dataset of all kidney biopsies performed in Scotland. First kidney biopsies performed between 2014 and 2017 inclusive, with evidence of AAV, were included. Demographic and histological data and outcomes including relapse, end-stage kidney disease (ESKD) and death were recorded. The ARRS is an aggregate of individual scores incorporating the percentage of normal glomeruli, the percentage of tubular atrophy/interstitial fibrosis and eGFR (CKD-EPI) at time of biopsy. Then, depending upon aggregate score, patients are assigned to a high, medium or low risk group. For deprivation, the validated Scottish Index of Multiple Deprivation (SIMD) was used as a measure of relative socioeconomic deprivation for each patient. Patients were assigned to deprivation quintiles, ranked from 1st (most deprived) to 5th (least deprived). Cox proportional hazard models were created for survival to ESKD, relapse and death and stratified by ARRS group and then SIMD quintile. Statistical analyses were conducted using R software. <strong>Results:</strong> There were 241 patients eligible for inclusion: 38 (15.8%) relapsed, 35 (14.5%) progressed to ESKD and 54 (22.4%) died. Mean age at biopsy was 66.7±12.2 years and 52% (n=129) were male; this was similar across the risk groups. Patients were stratified into low (n=123 (50%)), medium (n=112 (46%)) and high (n=11 (5%)) ARRS groups respectively. Within the high-risk group, mean eGFR was lower (high 8.6±6.1 versus low risk 45.7±26.0 ml/min/1.73m2, p&lt;0.001). Proteinuria levels were higher (high 405 (IQR 170-767) versus low risk 81 (IQR 41-155) mg/mmol, p&lt;0.001). Ninety-one (38%) were PR3 antigen positive and PR3 positive patients were over-represented in the high risk compared with the low risk group (70% versus 43% respectively; p=0.006). High risk patients were more likely to receive plasma exchange (80% versus 9%; p&lt;0.001) and/or haemodialysis (70% versus 2%; p&lt;0.001) compared with low risk patients. Relapse was progressively less common with increasing ARRS (low risk: 21.3%; medium risk 11.0%; high risk 0.0%; p=0.038). On Cox proportional hazards analysis, the need for initial kidney replacement therapy (HR 4.6 (95% CI 1.4-14.7); p=0.011) and ARRS (medium risk: HR 9.3 (95% 2.1-42.1) p=0.004; high risk: HR 29.9 (95% CI 3.7 – 239.7) p=0.001) were associated with higher risk of ESKD. High ARRS was associated with a trend towards increased risk of death (HR 1.14 (95% CI 0.99-1.31); p=0.073). There was a trend towards those in the least deprived quintile being older. Otherwise, no significant difference between deprivation quintiles was observed for baseline demographics, presence of pulmonary haemorrhage or treatment modality. After multiple adjustments relative socioeconomic deprivation was not associated with relapse nor ESKD but was associated with an increased risk of death overall (HR 3.44 for most deprived compared to least deprived quintiles [95% CI 1.02-11.57], p=0.046). <strong>Conclusions:</strong> A simple RRS, calculated using routinely collected data, can predict progression to ESKD in those with AAV proven on first kidney biopsy. It may also play a role in predicting relapse, with those in the low risk group most likely to relapse. This could be explained by reduced irreversible damage in this group. Furthermore, our analyses did not demonstrate an association with socioeconomic deprivation and worse kidney outcomes for AAV, but was associated with an increased risk of death. <strong>Disclosures:</strong> None.