Manifestations of patients with LN at the time of renal biopsy.
| Variables | 1994–1998, n = 182 | 1999–2004, n = 584 | 2005–2010, n = 1179 | p |
|---|---|---|---|---|
| Demographics | ||||
| Age at biopsy, yrs | 29.4 (24.8–34.7) | 30.6 (24.4–36.6) | 31.8 (23.5–39.5) | < 0.001 |
| Women | 157 (86.3) | 514 (88.0) | 1018 (86.3) | 0.60 |
| Medical history | ||||
| Duration of SLE, mos | 26.1 (7.2–66.0) | 19.3 (5.2–59.5) | 20.1 (4.0–61.7) | 0.03 |
| Duration of LN, mos | 7.53 (3.2–25.0) | 6.1 (2.0–25.2) | 4.9 (1.6–25.9) | 0.01 |
| Previous treatment with immunosuppressive agents | 149 (81.9) | 447 (76.5) | 872 (74.0) | 0.08 |
| Prior renal biopsy | 3 (1.6) | 34 (5.8) | 155 (13.1) | < 0.001 |
| Prior dialysis | 0 (0.0) | 6 (1.0) | 26 (2.2) | 0.06 |
| Clinical severity | ||||
| SLEDAI | 10.0 (7.0–13.0) | 12.0 (8.0–14.0) | 12.0 (10.0–16.0) | < 0.001 |
| Hypertensiona | 83 (45.6) | 215 (36.8) | 426 (36.1) | 0.05 |
| Anemiab | 152 (83.5) | 468 (80.1) | 921 (78.1) | 0.20 |
| Hypoalbuminemiac | 120 (65.9) | 347 (59.4) | 648 (55.0) | 0.01 |
| Serum creatinine, mg/dl | 0.99 (0.83–1.43) | 0.88 (0.71–1.17) | 0.75 (0.59–1.07) | < 0.001 |
| eGFR, ml/min/1.73 m2 d | ||||
| ≥ 90 | 71 (39.0) | 301 (51.5) | 756 (64.1) | < 0.001 |
| 60–89 | 54 (29.7) | 156 (26.7) | 201 (17.0) | < 0.001 |
| 30–59 | 34 (18.7) | 78 (13.4) | 148 (12.6) | 0.08 |
| < 30 | 23 (12.6) | 49 (8.4) | 74 (6.3) | 0.006 |
| Urinary protein, g/day | 1.94 (1.18–2.96) | 2.58 (1.24–5.15) | 2.39 (1.20–4.37) | < 0.001 |
| < 0.4 | 6 (3.3) | 31 (5.3) | 58 (4.9) | 0.54 |
| 0.4–3.49 | 144 (79.1) | 326 (55.8) | 708 (60.1) | < 0.001 |
| ≥ 3.5 | 32 (17.6) | 226 (38.7) | 413 (35.0) | < 0.001 |
| Urine RBC, × 104/ml | 22.5 (4.0–160.0) | 41.0 (4.0–181.0) | 47.0 (5.0–186.5) | 0.04 |
| Uric acid, μmol/l | 384 (310–489) | 394 (317–498) | 378 (301–470) | 0.04 |
| Serum C3, g/l | 0.56 (0.38–0.87) | 0.46 (0.35–0.66) | 0.50 (0.38–0.69) | < 0.001 |
| Serum C4, g/l | 0.25 (0.13–0.40) | 0.11 (0.07–0.16) | 0.10 (0.06–0.15) | < 0.001 |
| Anti-dsDNA–positive | 92 (50.5) | 248 (42.5) | 626 (53.1) | < 0.001 |
| Pathologic features | ||||
| Pathologic classification | ||||
| Class II | 12 (6.6) | 48 (8.2) | 58 (4.9) | 0.02 |
| Class III/III+V | 37 (20.3) | 151 (25.9) | 314 (26.6) | 0.20 |
| Class IV/IV+V | 115 (63.2) | 308 (52.7) | 621 (52.7) | 0.03 |
| Class V | 18 (9.9) | 77 (13.2) | 186 (15.8) | 0.06 |
| Pathologic AI | 8.0 (3.0–11.0) | 6.0 (2.0–10.0) | 7.0 (2.0–11.0) | 0.05 |
| Pathologic CI | 2.0 (1.0–4.0) | 2.0 (0.0–3.0) | 2.0 (0.0–3.0) | 0.05 |
| High AI (≥ 12) | 38 (20.9) | 100 (17.1) | 233 (19.8) | 0.34 |
| High CI (≥ 4) | 49 (26.9) | 108 (18.5) | 217 (18.4) | 0.02 |
| Followup frequency, visits/year | 1.6 (1.1–2.4) | 2.4 (1.7–3.2) | 3.3 (2.5–4.4) | < 0.001 |
Values are n (%) or median (interquartile range).
↵a Hypertension was defined as systolic blood pressure ≥ 140 mmHg or diastolic blood pressure ≥ 90 mmHg.
↵b Anemia was defined as hemoglobin < 120 g/l (women) or < 130 g/l (men).
↵c Hypoalbuminemia was defined as serum albumin < 30g/l.
↵d The eGFR was calculated using the Chronic Kidney Disease Epidemiology Collaboration equation: 141 × min (SCr/κ, 1) α × max (SCr/κ, 1)–1.209 × 0.993age × 1.018 (if female), where κ is 0.7 for females and 0.9 for males, α is −0.329 for females and −0.411 for males, min indicates the minimum of SCr/κ or 1, and max indicates the maximum of SCr/κ or 1. SI conversion factors: to convert SCr to μmol/l, multiply values by 88.4. LN: lupus nephritis; SLE: systemic lupus erythematosus; SLEDAI: Systemic Lupus Erythematosus Disease Activity Index; eGFR: estimated glomerular filtration rate; RBC: red blood cells; AI: activity index; CI: chronicity index; SCr: serum creatinine.