Table 1: Summarizing patient demographics, clinical findings and treatment outcomes between subgroups. All values are median [inter-quartile range] unless otherwise stated. Legend: SpAD – Spondyloarthritis or associated disease, AI – Other autoimmune disease, iLVV – idiopathic large vessel vasculitis, CRP – C-reactive Protein, ESR – Erythrocyte sedimentation rate, PET-CT – Positron-emission Tomography, SUV – standard uptake value, MRI – magnetic resonance imaging.

			iLVV		SpAD		AI		p-value
Patient Demographics
	n		33		16		13
	Female, n (%)		26	(79%)	11	(69%)	11	(85%)	0.58
	Never Smoker, n (%)		14	(42%)	6	(38%)	3	(23%)	0.41
	Age at Diagnosis, yrs		70.3	[59.3-73.3]	59.2	[54.0-63.8]	68.1	[58.7-72.3]	0.01
	Follow-up, mts		11	[3-36]	38	[18-63]	39	[7-52]	0.01
Clinical Features
	Fever, n (%)		7	(21%)	7	(44%)	4	(31%)	0.22
	Weight loss, n (%)		21	(64%)	8	(50%)	7	(54%)	0.73
	Night Sweats, n (%)		16	(48%)	9	(56%)	6	(46%)	0.71
	Myalgia, n (%)		22	(67%)	9	(56%)	7	(54%)	0.70
	Headache, n (%)		18	(55%)	8	(50%)	4	(31%)	0.34
	Jaw claudication, n (%)		10	(30%)	2	(13%)	3	(23%)	0.44
	Symptom Duration, d		92	[53-203]	97	[38-201]	79	[53-181]	0.91
Laboratory Parameters
	Leucocytes, Tsd/µl		8.8	[7.8-10.0]	9.1	[8.2-10.7]	10.6	[7.5-11.0]	0.73
	CRP, mg/l		90	[50-120]	73	[37-118]	107	[31-149]	0.67
	ESR, mm/hr		76	[69-93]	79	[58-88]	81	[62-100]	0.90
Imaging									0.46
	PET-CT, n (%)		21	(64%)	7	(44%)	8	(62%)
	- SUVmax		4.4	[3.2-6.0]	3.1	[2.9-3.2]	3.5	[3.3-4.7]	0.305
	MRI, n (%)		8	(24%)	6	(38%)	3	(23%)
	Site affected
	- Ascending Thoracic Aorta, n (%)		24	(83%)	12	(92%)	6	(55%)	0.05
	- Descending Thoracic Aorta, n (%)		27	(93%)	10	(77%)	9	(82%)	0.21
	- Abdominal Aorta, n (%)		26	(90%)	8	(62%)	8	(73%)	0.08
	- Other large vessel, n (%)		20	(69%)	7	(54%)	6	(55%)	0.43
	No. of Sites affected
	- Single site, n (%)		4	(14%)	1	(8%)	4	(36%)	0.14
	- ≥3 Sites, n (%)		23	(79%)	8	(62%)	6	(55%)	0.24
Treatment									0.39
	Standard Protocol, n (%)		22	(67%)	13	(81%)	10	(77%)
	Steroids only, n (%)		11	(33%)	3	(19%)	3	(23%)
Outcomes
	Relapsing Patients, n (%)		12	(36%)	8	(50%)	6	(46%)	0.62
	Refractory Disease, n (%)		2	(6%)	5	(31%)	3	(23%)	0.05