18. Clinical features and outcome in systemic polyarteritis nodosa patients since 2005: data from 196 patients

Background: The etiological landscape of systemic polyarteritis nodosa (PAN) have substantially changed since hepatitis B virus (HBV) vaccination and the description of new entities such as adenosine deaminase 2 (ADA2) deficiency or myelodysplastic syndrome (MDS) associated PAN. Recent data regarding systemic PAN characteristics and predictors of relapse are lacking. Methods: Retrospective study including patients with systemic PAN referred to the French Vasculitis study Group (FVSG) from 2005 to 2019. Clinical characteristics, associated conditions and long-term outcomes were collected in order to identify predictors of relapse. Results: Overall, 196 patients with systemic PAN were included. The most frequent clinical manifestations were constitutional symptoms (84%), cutaneous symptoms (67%), musculoskeletal symptoms (58%) and neurological symptoms (54%). Secondary PAN represented 28% of patients and were associated with MDS (9%), active cancer (7%), lymphoproliferative disorder (4%), autoinflammatory syndrome (4%) and hypereosinophilic syndrome (2,5%). No patient had active HBV infection at the time of PAN diagnosis. Most of the patients (98%) received a first line treatment with steroids alone (41%) or associated with an immunosuppressive agent (58%) achieving remission in 173 (90%) cases whereas 20 (10%) patients were non responders. During a median follow-up of 43 (16-90) months, 76 (39%) patients experienced a relapse after a median interval of 23 (8-45) months. Overall, 25 (13%) patients died with a 1-, 5- and 10-years overall survival rate of 91.4%, 88.8% and 87.8% respectively. In multivariable analysis, age >65 years (OR 2.11, 95% CI 1.27 to 3.51, P=0.004), severe gastrointestinal (GI) involvement (OR 2.57, 95% CI 1.40 to 4.71, P=0.002) and skin involvement (OR 1.99, 95% CI 1.21 to 3.29, P=0.007) were associated with a higher risk of relapse, while treatment with cyclophosphamide was associated with a decreased risk of relapse (OR 0.56, 95% CI 0.35 to 0.90, P=0.016). Conclusions: Although HBV vaccination allowed a decreased incidence of HBV related PAN, 28% of systemic PAN in France are associated with another condition. The rates of relapse remain high, especially in patients with GI or cutaneous involvement. Disclosures: non