Table 1.

Demographic, anthropometric, and clinical characteristics of patients. Data are expressed as mean (±standard deviation, SD), if not otherwise specified. The level of statistical significance was set at a p-level of 0.05. n.s. = not significant; * = p < 0.05; ** = p < 0.01; n.a. = not assessed. IBP = inflammatory back pain; jSpA = juvenile spondyloarthritis; PDUS = power Doppler ultrasound; BMI = body mass index; ESR = erytrosedimentation rate; CRP = C-reactive protein; JSpADA = juvenile spondyloarthritis disease activity; SIJ = sacroiliac joint; RI = resistive index; BME = bone marrow edema; BUSES = Belgrade Ultrasound Enthesitis Score.

Patients Characteristics	Overall Population	Final jSpA Diagnosis	Not jSpA	Statistical Significance
Number of patients (female/male)	20 (13/7)	12 (8/4)	8 (5/3)	n.s.
Age, in years (±SD)	14.2 (±2.95)	14.6 (±2.75)	13.9 (±2.53)	n.s.
BMI percentile(±SD)	67.6 (±26.8)	74.3 (±24)	54.2 (±29.7)	n.s.
ESR mm/h(±SD)	23.8 (±22.9)	28.9 (±25.2)	11 (±8.08)	n.s.
CRP mg/dL (±SD)	1.04 (±1.58)	1.31 (±1.79)	0.51 (±1.01)	n.s.
jSpADA (±SD)	2.75 (±1.89)	2.75 (±1.89)	n.a.	n.a.
-Patients with PDUS+ -SIJs with PDUS+	19 patients (95%) 30 SIJs (75%)	12 patients (100%) 21 SIJs (87.5%)	7 patients (87.5%) 9 SIJs (56.2%)	n.s. n.s.
SIJs PD grading (±SD) patient level	1.20 (±0.523)	1.42 (±0.515)	0.875 (±0.354)	p = 0.012 *
SIJs PD grading (±SD) joint level	0.912 (±0.668)	1.13 (±0.612)	0.563 (±0.512)	p = 0.003 **
SIJs RI (±SD) patient level	0.583 (±0.115)	0.534 (±0.092)	0.656 (±0.112)	p = 0.024 *
SIJs RI (±SD) joint level	0.671 (±0.181)	0.604 (±0.155)	0.767 (±0.176)	p = 0.005 **
MRI SIJs BME lesions	12 patients (60%) 22 SIJs (55%)	12 patients (100%) 22 SIJs (91.6%)	0 0	n.a.
MRI SIJs capsulitis/enthesitis	6 patients (30%) 11 SIJs (27.5%)	6 patients (50%) 11 SIJs (45.8%)	0 0	n.a.
MRI lumbar spine inflammatory involvement	5 patients (25%)	5 patients (41.6%)	0	n.a.
Patients with US enthesitis total amount of US enthesitis BUSES (mean)	4 patients (20%) 8 1.8	3 (25%) 6 1.83	1 (12.5%) 2 1.75	n.s. n.s. n.s.