Background Polyarteritis Nodosa (PAN) is the first described but the least frequent primary systemic vasculitis. Various subgroups of necrotizing vasculitis have separated out from PAN, and are now defined such as HBV-related, cutaneous PAN or monogenic forms of vasculitis. There is a paucity of information on the current phenotypes and, ethnic and geographic differences of PAN.
Objectives This study compares the demographic and clinical features between two PAN cohorts.
Methods A retrospective survey of databases from two vasculitis centres between 1990–2016 for PAN patients fulfilling the EMEA Vasculitis Classification algorithm. All paediatric patients met the Ankara 2008 (EULAR/PReS endorsed) criteria for childhood PAN. Patients with typical angiographic and/or histopathologic findings consistent with PAN were included. Demographics, and clinical characteristics, Disease Extent Index (DEI) and Vasculitis Damage Index were recorded. A subgroup analysis based on disease extent between the UK patients with Turkish (TR) patients was performed.
Results 93 (M/F: 51/42) patients (UK: 47, TR: 46) were recruited into the study. The mean age was 46.7 (20.7) years. Three were HBV-related, 20 (21.5%) had paediatric onset, 16 (16.5%) were cutaneous PAN.
Turkish patients had younger disease of onset (28.7 (17.8) vs. 43.0 (18.0), p<0.001). Twelve (26%) of Turkish patients had a monogenic disease (FMF association in 7, DADA2 in 5).
Cutaneous PAN was more frequent in the UK group (12 pts vs. 4pts, p=0.031) whereas renal involvement was increased in the TR group (Table). In contrast to systemic involvement, female predominance was seen in cutaneous PAN (40.3% vs. 68.8%, p=0.037). DEI was similar in both systemic involved groups (6.1 (2.4) vs. 6.5 (2.3), p=0.428). No difference was found between paediatric and adult onset patients except for frequency of cutaneous lesions (100% vs. 64.3%, p=0.002).
During a median 67.5 (32–126) months follow up, 13 patients deceased. No difference was found between the groups regarding relapse rate, death and vasculitis damage index (Table).
Conclusions Even though, the Turkish group had a younger disease onset and higher additional monogenic disease; disease extent, relapse rate, death, and damage index were similar in both groups. Among the cutaneous PAN group there was a female predominance. A multi-centre GWAS study could highlight the impact of genetic background on disease presentation and severity.
Disclosure of Interest None declared