THU0459 Survival of biopsy proven giant cell arteritis in northern italy: correlation with clinical, laboratory and histopathological findings
Authors: P. Macchioni, L. Boiardi, F. Muratore, M. Catanoso, A. Cavazza, P. Mancuso, L. Cimino, G. Restuccia, C. Salvarani
Journal: Annals of the Rheumatic Diseases (2018)

<h3>Objectives</h3> To correlate survival with clinical, laboratory and histopathological findings in a population based cohort of patients with biopsy-proven giant cell arteritis (GCA) living in the Reggio Emilia area during a 26 years period. <h3>Methods</h3> In this population-based study, all patients living in the Reggio Emilia area who underwent temporal artery biopsy (TAB) for suspected GCA from January 1, 1986 to December 31, 2012 were identified. A pathologist with expertise in vasculitis and blinded to clinical data and final diagnosis reviewed all TABs. Based on the localization of the inflammation, positive TABs were classified into 4 categories: small vessel vasculitis (SVV), with inflammation limited to small periadventitial vessels devoid of muscular coat; vasa vasorum vasculitis (VVV), with inflammation surrounding the adventitial vasa vasorum; inflammation limited to adventitia (ILA), with inflammation spreading from vasa vasorum to the adventitia without extension to the media; transmural inflammation (TMI), with external elastic lamina disruption and extension of the inflammation to the media. Histopathologic features evaluated were: the severity of inflammation and intimal hyperplasia, both graded on a semiquantitative scale (mild=1, moderate=2 severe=3), the presence of intraluminal acute thrombosis, calcifications, giant cells, fibrinoid necrosis and laminar necrosis. Information about clinical manifestations, laboratory findings, treatment and disease course were collected. Patients were followed from GCA diagnosis to death, migration or December 2013. <h3>Results</h3> 281 patients (206 female, 73.3%) with biopsy-proven GCA were identified in the study period. 120 patients (84 female, 70%) died during a median follow-up period of 96 (IQR 55, 143) months. At univariate analysis, the presence of polymyalgia rheumatica (PMR) (HR 0.54, 95% CI 0.37–0.79, p=0.002), higher level of haemoglobin (HR 0.84, 95% CI 0.74–0.96, p=0.011) at disease onset, long-term remission (HR 0.47, 95% CI 0.26–0.86, p=0.015) and ILA or VVV at TAB (HR 0.48, 95% CI 0.24–0.97, p=0.041) were associated with lower mortality, while the evidence of large vessel involvement at imaging studies performed at diagnosis was associated with increased mortality (HR 5.84, 95% CI 1.57–21.8, p=0.009). Multivariate analysis confirmed the association between lower mortality and PMR (HR 0.54, 95% CI 0.36–0.81, p=0.003), higher level of haemoglobin (HR 0.83, 95% CI 0.69–0.99, p=0.049) at disease onset, and ILA or VVV at TAB (HR 0.38, 95% CI 0.17–0.82, p=0.014), and between increased mortality and large vessel involvement at imaging studies performed at diagnosis (HR 5.31, 95% CI 1.39–20.26, p=0.014). <h3>Conclusions</h3> PMR at diagnosis and only adventitial inflammation at TAB seem to identify subsets of biopsy-proven GCA patients with more benign disease, while large vessel involvement at diagnosis a subset with reduced survival. <h3>Disclosure of Interest</h3> None declared