Table 2

Baseline clinical features of pediatric- and adult-onset systemic lupus erythematosus (pSLE and aSLE) patients based on osteopontin (OPN) quartiles*

pSLE

aSLE

OPNlo

OPNhi

P-value

OPNlo

OPNhi

P-value

Current prednisone dosage, mg/day, median (range)

10 (0, 60)

30 (0, 40)

0.6

5 (0, 5)

12.5 (0, 60)

0.1

High cumulative prednisone dose, patients, number (%)

2 (13)

8 (73)

0.01

1 (25)

3 (27)

0.3

Current immunosuppressive use, patients, number (%)

7 (44)

7 (64)

0.6

2 (25)

5 (46)

0.6

Renal involvement, patients, number (%)

8 (50)

8 (73)

0.4

0 (0)

4 (36)

0.5

Disease duration, years

2.3 ± 2.7

4.5 ± 3.5

0.2

8.5 ± 12.3

11.8 ± 7.6

0.7

SDI, median (range)

0 (0, 3)

2 (0, 5)

0.01

0 (0, 2)

0 (0, 2)

0.9

SLEDAI, median (range)

2 (0, 8)

2 (0,16)

0.3

2 (0, 8)

4 (0, 8)

0.6

ESR

18 ± 7

54 ± 28

0.01

8 ± 6

45 ± 35

0.1

C3

100 ± 32

95 ± 40

0.7

115 ± 15

89 ± 24

0.9

C4

15 ± 5

0.7

22 ± 3.3

19.2 ± 5.5

0.3

αdsDNA, % patients negative/% patients positive

46/8

40/40

< 0.0001

100/0

43/29

< 0.0001

αRBP, % patients positive

25

45

0.003

20

43

0.0005

*Except where otherwise indicated, values are expressed as mean ± standard deviation. The lowest and highest quartile of OPN (OPNlo and OPNhi) were defined as circulating plasma OPN levels < 7.8 ng/ml (n = 16 in pSLE and 11 in aSLE) or > 19.1 ng/ml (n = 4 in pSLE and 11 in aSLE), respectively. High cumulative prednisone dose was defined as > 300 mg/kg in pSLE and > 20 g in aSLE. SDI, Systemic Lupus International Collaborating Clinics/American College of Rheumatology (SLICC/ACR) damage index; SLEDAI, SLE, disease activity index; ESR, erythrocyte sedimentation rate; C3 and C4, complement 3 and 4; αdsDNA, anti-dsDNA antibody; borderline positive results were not included. αRBP, anti-RNA binding protein antibody.

Rullo et al. Arthritis Research & Therapy 2013 15:R18   doi:10.1186/ar4150