Table 1.

Group characteristics.*

diagnosis	psoriatic arthritis	rheumatoid arthritis	normal subjects
count	41	139	147
female	23 (56.1%)	122 (87.8%)	124 (84.4%)
male	18 (43.9%)	17 (12.2%)	23 (15.6%)
age [years]	50.2 ± 14.2	58.1 ± 13.4	54.4 ± 13.9
(range)	(23 - 77)	(19 - 81)	(20 - 89)
disease duration [months]	48	72	-
(range)	(1 - 288)	(0,5 - 480)
ESR [mm/h]	39.3 ± 26.9	38.7 ± 26.2	29.9 ± 22.9
(range)	(2 - 118)	(2 - 109)	(2 - 102)
CRP [mg/L]	10	8.4	4.8
(range)	(0.14 - 84)	(0.2 - 197)	(0.2 - 320)
RF positive	2 (4.9%)	92 (66.2%)	7 (4.7%)
RF titer [UI/mL]	10.9 ± 7,8	56	14.3 ± 10.8
(range)	(2.2 - 42)	(4.8 - 953)	(3.4 - 106)
anti-CCP positive	5 (12.2%)	84 (60.4%)	2 (1.4%)
anti-CCP titer [UI/mL]	2	14	2.5 ± 1.5
(range)	(0.1 - 27)	(0.1 - 200)	(0.1 – 5.8)
polyarticular involvement&	17 (41.5%)	139 (100%)	0
glucocorticoids treatment	3 (7.3%)	44 (31.6%)	0
DMARD treatment	35 (85.4%)	122 (87.8%)	0
biologic treatment	4 (9.8%)	6 (4.3%)	0
Notes: * numeric data are reported either as means with standard deviation and interval, or as medians with extremes. & polyarticular involvement = 5 or more affected joints.