Baseline characteristics of the patients in the per-protocol population
| Characteristics | IST continuation (N=40) | IST discontinuation (N=44) |
| Mean (SD) N (%) | Mean (SD) N (%) | |
| Age, years | 37.5 (14.0) | 36.7 (13.2) |
| Sex, female | 33 (82.5) | 38 (86.4) |
| Ethnicity | ||
| Caucasian | 27 (67.5) | 26 (59.1) |
| Black | 9 (22.5) | 14 (31.8) |
| Asian | 4 (10.0) | 4 (9.1) |
| SLE disease duration, years | 9.7 (10.2) | 7.6 (6.2) |
| Antiphospholipid syndrome | 5 (12.5) | 6 (13.6) |
| Menopause | 6/31 (19.4) | 10/38 (26.3) |
| Obesity (body mass index ≥30 kg/m2) | 5 (12.5) | 6 (13.6) |
| Systolic blood pressure, mm Hg | 121 (13) | 116 (14) |
| Diastolic blood pressure, mm Hg | 73 (11) | 73 (10) |
| First flare of proliferative LN | 32 (80.0) | 32 (72.7) |
| Induction therapy | ||
| Low-dose intravenous cyclophosphamide | 26 (65.0) | 24 (54.5) |
| Mycophenolate mofetil | 14 (35.0) | 20 (45.5) |
| Maintenance IST | ||
| Duration, years | 2.8 (0.9) | 2.8 (0.8) |
| Mycophenolate mofetil | 30 (75.0) | 36 (81.8) |
| Azathioprine | 10 (25.0) | 8 (18.2) |
| Doses prescribed (mg/day) | ||
| Mycophenolate mofetil | 1633 (571) | 1364 (684) |
| Azathioprine | 82.5 (29) | 81.2 (39) |
| Corticosteroids | 4.3 (2.8) | 4.3 (2.8) |
| Hydroxychloroquine | 365 (89) | 334 (131) |
| Hydroxychloroquine serum level, ng/L | 861 (714) | 644 (428) |
| Serum creatinine, µmol/L | 67.7 (14.7) | 72.7 (17.2) |
| Estimated GFR, mL/min/1.73 m² | 101.6 (28.0) | 94.9 (25.8) |
| Urinary protein/creatinine ratio, g/g | 0.28 (0.38) | 0.21 (0.28) |
| Urinary protein/creatinine ratio ≤0.2 g/g | 26 (65.0) | 29 (65.9) |
| Urinary protein/creatinine ratio ≤0.5 g/g | 34 (85.0) | 42 (95.5) |
| Urinary protein/creatinine ratio ≤0.7 g/g | 35 (87.5) | 43 (97.7) |
| Serum albumin, g/dL | 4.2 (0.5) | 4.2 (0.5) |
| Haemoglobin, g/L | 1.30 (0.18) | 1.29 (0.13) |
| Leucocytes, G/L | 5.71 (1.7) | 5.58 (2.4) |
| Lymphocytes, G/L | 1.5 (0.7) | 1.39 (0.6) |
| Platelets, G/L | 255 (89) | 240 (79) |
| Low C3 | 5/38 (13.2) | 5/42 (11.9) |
| Low C4 | 4/38 (10.5) | 4/42 (9.5) |
| Positive anti-dsDNA | 24/38 (63.2) | 24/44 (54.5) |
| SLEDAI score | 2.2 (1.7) | 1.6 (1.8) |
Data are expressed as mean (SD), number (%) or number/number available (%).
GFR, glomerular filtration rate; IST, immunosuppressive therapy; LN, lupus nephritis; SLE, systemic lupus erythematosus; SLEDAI, SLE Disease Activity Index.