Parameters All subjects n=100 Active LN n=47 Inactive LN n=53 p value
Age, mean ± SD years 336.90 ± 10.62 36.40 ± 9.97 37.33 ± 11.24 0.74
- Female: no. (%) 92 (92) 43 (91.5) 49 (92.5) 0.57
- Male: no. (%) 8 (8) 4 (8.5) 4 (7.5)  
 Race: no. (%)
- Malay 41(41) 24 (51.1) 17 (32.1) 0.14
- Chinese 55 (55) 21 (44.7) 34 (64.2)  
- Indian 4 (4) 2 (4.3) 2 (3.8)  
 LN duration in years 7 (1–24) 7 (1–24) 7 (1–17) 0.56
Mixed connective tissue disease (MCTD) 7 (7%) 3 (6.4) 4 (7.5) 0.82
Musculoskeletal system (MSK) 41 (41%) 20 (42.6) 21 (39.6) 0.46
- Duration of MSK in years 6 (1–27) 6.5 (1–27) 6 (1–27) 0.60
Autoimmune Haemolytic Anaemia (AIHA) 26 (26%) 14 (29.8) 12 (22.6) 0.27
- Duration of AIHA in years 4.88 ± 3.21 5.58 ± 3.44 4.28 ± 2.99 0.34
Idiopathic thrombocytopenic purpura (ITP)  9 (9%) 5 (10.6) 4 (7.5) 0.24
- Duration of ITP in years 7.5 ± 4.62 9.5 ± 5.8 5.5 ± 2.38 0.20
Thrombotic thrombocytopenic purpura (TTP)  1 (1%) 0 1 (1%) 0.53
 Systolic blood pressure (mmHg) 128 ± 17.68 128 ± 13.16 120 ± 13.91 0.001
Diastolic blood pressure (mmHg) 75.2 ± 4.08 77.80 ± 10.31 73.68 ± 10.44 0.04
Classes of lupus nephritis (%)
- WHO class I 1 (1) 1 (2.1) 0 (0) 0.71
- WHO class II ± V 6 (6) 3 (6.4) 3 (5.7)  
- WHO class III ± V 34 (34) 15 (31.9) 19 (35.8)  
- WHO class IV ± V 52 (52) 26 (55.3) 26 (49.1)  
- WHO class V 5 (5) 1 (2.1) 4 (7.5)  
- WHO class VI 2 (2) 1 (2.1) 1 (1.9)  
 Activity index median (IQR) 8 (0–19) 9 (0–16) 8 (0–19)  0.93
 Chronicity index median (IQR) 3 (0–15) 3.58 (0–9) 3 (1–15)  0.55
 CKD stage
- Stage 1 (eGFR > 90) 61 (61) 25 (53.2) 36 (67.9) 0.06
- Stage 2 (eGFR 60 - 89) 22 (22) 10 (21.3) 12 (22.6)  
- Stage 3 (eGFR 30 - 59) 14 (14) 9 (19.1) 5 (9.4)  
- Stage 4 (eGFR 15 - 29) 3 (3) 3 (6.4) 0 (0%)  
Medications, no (%)
- Corticosteroids 95 (95) 43 (91.5) 52 (98.1) 0.12
- Cumulative dose for previous six months (g) 1.80 (0.75–4.50) 1.80 (0.90–4.50) 1.76 (0.75–1.95) 0.001
- Cumulative dose from previous relapse (g) 5.040 (0.90–24.43) 4.415 (0.90–24.43) 6.685 (1.59–13.32) 0.009
- Time from last relapse (months) 22 (1–120) 11 (1–120) 28 (3.5–72) 0.001
- Cyclophosphamide 8 (8) 8 (17) 0 (0) 0.002
- Cyclosporine A/Tacrolimus 30 (30) 19 (40.4) 11 (20.8) 0.03
- Mychophenolic acid 22 (22) 12 (25.5) 10 (18.9) 0.42
- Azathioprine 36 (36) 12 (25.5) 24 (45.3) 0.04
- Hydroxychloroquine 42 (42) 20 (42.6) 22 (41.5) 0.91
- Renin angiotensin system blockers (ACEI / ARB/ Spironolactone) 68 (68) 29 (61.7) 39 (73.6) 0.11
- Other antihypertensive agents
- Calcium channels blockers 28 (28) 12 (25.5) 16 (30.1) NS
- Beta blockers 13 (13) 6 (12.7) 7 (13.2) NS
- Alfa blockers 1 (1) 1 (1) 0 (0) NS
- Lipid lowering agents 39 (39) 20 (42.5) 19 (35.8) NS
- Aspirin 13 (13) 4 (8.5) 9 (17) 0.20
SD: Standard Deviation; IQR: Interquartile Range; LN: Lupus Nephritis; WHO: World Health Organization; CKD: Chronic Kidney Disease; ACEI: Angiotension Converting Enzyme Inhibitors; ARBs: Angiotensin Receptor Blockers; NS: Not Significant
Table 2: Demographic and baseline characteristics in the Active and Inactive LN patient groups.