Table 1 Demographic characteristics of the patients included in the study

Number of samples (%)

662 (53.7 %)

266 (21.6 %)

171 (13.9 %)

174 (14.1 %)

1233 (100 %)

Number of patients (%)

208 (64.6 %)

42 (13.0 %)

29 (9 %)

43 (13.3 %)

322 (100 %)

Females, n (%)

177 (85.1 %)

32 (76.2 %)

23 (79.3 %)

37 (86.0 %)

269 (83.5 %)

Males, n (%)

31 (14.9 %)

10 (23.8 %)

6 (20.7 %)

6 (14.0 %)

53 (16.5 %)

Whites, n (%)

118 (56.7 %)

23 (54.8 %)

11 (37.9 %)

21 (48.8 %)

173 (53.7 %)

Blacks, n (%)

37 (17.8 %)

7 (16.7 %)

6 (20.7 %)

12 (27.9 %)

62 (19.3 %)

Asians, n (%)

21 (10.1 %)

6 (14.3 %)

5 (17.2 %)

4 (9.3 %)

36 (11.2 %)

Other ethnicities, n (%)

32 (15.4 %)

6 (14.3 %)

7 (24.1 %)

6 (14.0 %)

51 (15.8 %)

Disease duration, yr (SD)

13.02 ± 10.38

8.90 ± 6.23

11.54 ± 9.49

8.61 ± 8.07

11.76 ± 9.71

Age at first 24hP, yr (SD)

42.26 ± 14.88

37.02 ± 16.14

38.33 ± 13.66

35.05 ± 11.58

40.26 ± 14.76

Serum creatinine, μmol/L (SD)

84.39 ± 47.30

87.76 ± 42.56

87.76 ± 42.56

80.49 ± 58.02

84.18 ± 47.03

Patients taking prednisone, n (%)

79 (62.7 %)

22 (59.5 %)

16 (59.3 %)

31 (77.5 %)

148 (64.3 %)

Patients taking immunosuppressives, n (%)

70 (55.6 %)

25 (67.6 %)

14 (51.9 %)

28 (70.0 %)

137 (59.6 %)