Table 1 Comparison of baseline clinical and serological variables along with plasma vitamin D levels between the north Indian and south Indian centres

Age in years

(mean ± SD)

28.75 ± 11.04

30.01 ± 10.45

15 ± 3.02

15.53 ± 2.6

30.26 ± 9.12

31.17 ± 10

Females (%)

283 (93.1%)

370 (92.9%)

53 (91.38%)

39 (86.67%)

230 (93.5%)

331 (93.77%)

Duration of SLE in months

Median (IQR)

20 (39)

15 (23)*

11.5 (19)

12 (15)

24 (44.2)

15 25)*

BMI (mean ± SD)

21.36 ± 4.8

21.59 ± 5.1

16.7 ± 3.13

18.1 ± 3.99

21.64 ± 4.52

20.9 ± 4.6

Plasma vitamin D, median (IQR) ng/ml

17.15 (16.07)

27.06 (20.21)*

17.64 (14.31)

21.04 (19.31)

20.27 (17.3)

25.5 (13.92)*

Vitamin D deficient (≤ 20 ng/ml) (%)

153 (50.33%)

138 (34.76%)*

32 (55.17%)

20 (44.44%)*

121 (49.19%)

118 (33.43%)*

Vitamin D insufficient (20.1–29.9 ng/ml) (%)

87 (28.62%)

121 (30.33%)*

22 (37.93%)

13 (28.89%)

65 (26.42%)

108 (30.59%)

Vitamin D sufficient (≥ 30 ng/ml) (%)

64 (21.05%)

139 (35.01%)*

4 (6.9%)

12 (26.67%)

60 (24.39%)

127 (35.98%)

SLEDAI 2K at baseline, median (IQR)

12 (8)

13 (11)

15 (10)

14 (12)

11 (8)

13.5 (11)

SLEDAI 2K > 4 (n, %)

204 (67.11%)

280 (70.53%)

46 (79.31%)

41 (91.1%)

158 (64.23%)

239 (67.71%)

C3 mg/dl

Median (IQR)

57.45 (51.45)

56.7 (53.5)*

48.5 (38.2)

73.5 (67.9)

65.5 (51.61)

62.7 (51.83)*

Low C3, n (%)

190 (62.5%)

257 (64.73%)

36 (62.07%)

33 (73.33%)

154 (62.6%)

224 (63.46%)

C4 mg/dl

Median (IQR)

11.34 (12.49)

9.53 (9.17)

9.13 (12.17)

10.35 (22.49)

11.4 (12.9)

9.38 (8.75)

Low C4, n (%)

149 (49.01%)

168 (42.1%)

28 (48.28%)

23 (51.11%)

121 (41.19%)

145 (41.08%)*

Low complements (C3/C4), n (%)

212 (69.74%)

278 (70.02%)

41 (70.69%)

36 (80%)

171 (69.51%)

242 (68.55%)

Anti-dsDNA (IU/ml)

Median (IQR)

158.11 (217.68)

521.67 (659.32)*

259 (235)

624 (641)*

136.4 (248)

458.6 (659)*

Positive anti-dsDNA, n (%)

210 (69.07%)

258 (64.74%)

41 (70.69)

35 (77.78)

169 (68.7)

223 (63.17)

CXCL-10 pg/ml, median (IQR) (n = 474)

223.96 (438.86)

138.69 (202.73)

293.26 (554.03)

178.69 (249.02)

207.13 (416.49)

130.28 (178.31)

Galectin 9 ng/ml, median (IQR) (n—548)

10.55 (11.45)

13.66 (17.20)*

9.99 (15.65)

11.79 (15.09)

10.78 (10.21)

14.03 (17.76)*

Renal, n (%)

141 (46.38%)

142 (35.76%)*

26 (44.83%)

19 (42.22%)

115 (46.75%)

123 (34.84%)*

CNS, n (%)

48 (15.79%)

65 (16.37%)

13 (22.41%)

5 (11.11%)

35 (14.23%)

60 (17%)

Mucocutaneous, n (%)

268 (88.15%)

366 (92.19%)*

53 (91.38%)

42 (95.56%)

215 (87.4%)

324 (91.78%)*