Spondyloarthropathies in Autoimmune Diseases and Vice Versa

Table 2

General characteristics of patients with SpAs.

	Classical classification [2]						New classification [3, 4]
	All (𝑛=144)^a	AS; (𝑛=80)	PsA; (𝑛=31)	uSpA (𝑛=24)	IBD-associated SpA (𝑛=6)	𝑃value	Axial (𝑛=89)	Peripheral (𝑛=55)	𝑃value
Mean (SD)
Age, years	43.78 (11.08)	42.23 (10.33)	50.81 (13.00)	41.28 (8.45)	38.96 (6.02)	𝑃<0.05^b, c	41.80 (10.15)	46.54 (11.84)	𝑃=0.018
Age at onset, years	34.77 (11.39)	33.24 (10.71)	41.23 (11.20)	33.71 (11.52)	29.33 (6.77)	𝑃<0.05^b	33.05 (10.42)	37.62 (12.35)	𝑃=0.017
Age at diagnostic, years	39.24 (10.98)	37.58 (10.27)	45.65 (12.43)	37.54 (9.31)	34.17 (7.83)	𝑃<0.05^b, c	37.40 (10.03)	42.00 (11.95)	𝑃=0.017
Characteristic, n (%)
Percentage	100	55.6	21.5	16.7	4.2	NA	60.13	37.16	NA
Male^d	82 (56.9)	45 (56.3)	20 (64.5)	13 (54.2)	2 (33.3)	NS	51 (57.39)	31 (56.4)	NS
Female	62 (43.1)	35 (43.8)	11 (35.5)	11 (45.8)	4 (66.7)	NS	38 (42.7)	24 (43.6)	NS
Low back pain	111 (77.1)	80 (100)	10 (32.3)	15 (62.5)	4 (66.7)	𝑃<0.001^b, c, e	89 (100)	50 (90.9)	𝑃<0.001
Peripheral arthritis	73 (50.7)	22 (27.5)	24 (77.4)	22 (91.7)	3 (50)	𝑃<0.001^b, c	23 (25.8)	50 (90.9)	𝑃<0.001
Enthesitis (heel)	26 (18.1)	18 (22.5)	2 (6.5)	4 (16.7)	2 (33.3)	NS	20 (22.5)	6 (10.9)	NS
Enthesitis (other sites)	34 (23.6)	19 (23.8)	6 (16.1)	8 (33.3)	2 (33.3)	NS	22 (24.7)	12 (21.8)	NS
Dactylitis	28 (19.4)	10 (12.5)	9 (29)	8 (33.3)	1 (16.7)	NS	11 (12.4)	17 (30.9)	𝑃=0.006
Psoriasis	28 (19.4)	0	28 (90.3)	0	0	𝑃<0.001^b, f, g	2 (2.2)	26 (47.3)	𝑃<0.001
IBD	6 (4.2)	0	0	0	6 (100)	𝑃<0.001^e, g, h	2 (2.2)	4 (7.3)	NS
HLA-B27
Positive	43/86 (50)	27/54 (50)	2/11 (18.2)	14/17 (82.35)	0	NA	29/59 (49.15)	14/27 (51.85)	NA
Negative	43/86 (50)	27/54 (50)	9/11 (81.8)	3/17 (17.65)	2/2 (100)	NA	30/59 (50.85)	13/27 (48.15)	NA
No data available	58/144 (40.3)	26/80 (32.5)	20/31 (64.5)	7/24 (29.16)	4/6 (66.66)	NA	30/89 (33.7)	28/55 (50.9)	NA

AS: ankylosing spondylitis, PsA: psoriatic arthritis, uSpA: undifferentiated spondyloarthropatty, IBD: inflammatory bowel disease, ReA: reactive arthritis, AD: autoimmune disease, HLA: human leukocyte antigen, NA: not applicable, and NS: non significant.
^aNeither ReA (𝑛=3) nor exclusive extraarticular SpA were included.
^bSignificant differences between AS and PsA.
^cSignificant differences between AS and uSpA.
^dSignificant differences in gender for all categories.
^eSignificant differences between AS and IBD-associated SpA.
^fSignificant differences between PsA and uSpA.
^gSignificant differences between PsA and IBD-associated SpA.
^hSignificant differences between uSpA and IBD-associated SpA.