Table 2 Univariable analysis of factors associated with serum NN and NA levels in patients with SLE

Gender *

Female (n = 336)

1

1

Male (n = 61)

2.01 (1.06, 3.81)

0.03

5.00 (2.50,9.98)

<0.001

Disease duration^†

Ratio given per 5-year increase

0.43 (0.23, 0.79)

0.005

0.32 (0.20,0.51)

<0.001

Age (at diagnosis)^†

Ratio given per 10-year increase

0.10 (0.02, 0.46)

<0.001

0.04 (0.01,0.16)

0.002

Ethnicity*

Caucasian (n = 182 )

1

1

Afro-Caribbean (n = 146 )

0.75 (0.47, 1.22)

2.07 (1.26,3.40)

Other (n = 69)

0.33 (0.17, 0.63)

0.003

3.75 (1.86,7.56)

<0.001

Any ENA**

No (n = 165)

1

1

Yes (n = 232)

3.43 (2.19, 5.37)

<0.001

3.19 (1.93,5.27)

<0.001

Anti-Ro**

No (n = 226)

1

1

Yes (n = 171)

1.70 (1.12, 2.59)

0.01

1.81 (1.14,2.89)

0.01

Anti-La**

No (n = 345)

1

1

Yes (n = 52)

0.79 (0.41, 1.50)

0.47

0.46 (0.20,1.06)

0.07

Anti-Sm**

No (n = 298)

1

1

Yes (n = 99)

5.63 (3.66, 8.67)

<0.001

6.25 (3.84,10.2)

<0.001

Anti-RNP**

No (n = 288)

1

1

Yes (n = 109)

1.08 (0.69, 1.70)

0.74

1.72 (1.06,2.79)

0.03

Anti-dsDNA level

<50 IU/ml (n = 177)

1

1

≥50 IU/ml (n = 170)

0.76 (0.26, 1.13)

0.17

1.32 (0.66,2.65)

0.43

C3 level

<0.9 g/l (n = 139)

1

1

≥0.9 g/l (n = 208)

0.83 (0.57, 1.20)

0.32

1.26 (0.86,1.87)

0.24

Disease activity in general system§

A, B (n = 31)

1

1

C, D, E (n = 344)

0.96 (0.60, 1.54)

0.87

1.19 (0.71,2.00)

0.52

Disease activity in mucocutaneous system

A, B (n = 41)

1

1

C, D, E (n = 334)

0.99 (0.63, 1.56)

0.95

1.32 (0.76,2.29)

0.33

Disease activity in neuropsychiatric system

A, B (n = 18)

1

1

C, D, E (n = 357)

0.56 (0.13, 2.38)

0.44

1.04 (0.50,2.19)

0.91

Disease activity in musculoskeletal system

A, B (n = 47)

1

1

C, D, E (n = 328)

1.20 (0.47, 3.04)

0.71

0.68 (0.43,1.05)

0.08

Disease activity in cardiorespiratory system

A, B (n = 13)

1

1

C, D, E (n = 362)

0.43 (0.24, 0.78)

0.006

1.40 (0.22,8.70)

0.72

Disease activity in vascular system

A, B (n = 12)

1

1

C, D, E (n = 363)

0.33 (0.17, 0.63)

0.001

0.39 (0.19,0.82)

0.01

Disease activity in renal system

A, B (n = 41)

1

1

C, D, E (n = 329)

1.09 (0.40, 2.97)

0.86

4.28 (2.13,8.58)

<0.001

Disease activity in hematological system

A, B (n = 95)

1

1

C, D, E (n = 280)

1.21 (0.84, 1.74)

0.30

1.44 (0.95,2.17)

0.08

Overall disease activity over last four assessments

Persistently low (n = 166)

1

1

Persistently mod/high (n = 209)

0.91 (0.66, 1.25)

0.57

0.66 (0.47,0.92)

0.01

Hydroxychloroquine

No (n = 223)

1

1

Yes (n = 174)

3.52 (2.40, 5.17)

<0.001

3.21 (2.08,4.95)

<0.001

Immunosuppression

No (n = 200)

1

1

Yes (n = 197)

1.66 (1.17, 2.34)

0.004

1.33 (0.89,1.98)

0.16

Oral corticosteroids

≤7.5 mg/day (n = 101)

1

1

>7.5 mg/day (n = 296)

0.81 (0.59, 1.13)

0.22

1.00 (0.69,1.44)

0.99

Albumin

Ratio given per 5 g/l increase

1.38 (1.20,1.59)

<0.001

1.42 (1.22,1.65)

<0.001