Demographic, histological and clinical features at second renal biopsy and at disease outcome in patients from different groups (expressed as mean (SD) unless differently specified)
| Variable | Overall | Group 1 Nephritic flare | Group 2 Proteinuric flare | Group 3 lack of response | P value |
| Number of patients | 92 | 28 | 46 | 18 | – |
| Age at second biopsy | 35.1 (10.6) | 34.7 (11.1) | 36.6 (10.36) | 31.7 (10.1) | 0.32 |
| Females, n (%) | 80 (86.9) | 26 (92.9) | 39 (84.8) | 15 (83.3) | 0.54 |
| Arterial hypertension, n (%) | 47 (51) | 24 (85.7) | 17 (36.9) | 6 (33.3) | 0.008 |
| Proteinuria, g/24 hours | 4.1 (3.5) | 6.0 (5.1) | 3.75 (2.41) | 2.1 (1.0) | 0.003 |
| SCr mg/dL | 1.4 (1.3) | 2.4 (1.7) | 0.8 (0.17) | 0.9 (0.3) | <0.001 |
| GFR ml/min/1.73 m2 | 71.9 (35) | 33.3 (14.1) | 94.8 (27.1) | 82.8 (30.3) | <0.001 |
| C3 mg/dL | 67.3 (29.3) | 61.8 (28.5) | 67.6 (28.8) | 75.6 (30.5) | 0.28 |
| C4 mg/dL | 17.6 (21.3) | 14.7 (20.8) | 20.4 (24.9) | 15.5 (.48) | 0.37 |
| Antibodies | |||||
| Anti-dsDNA in 87 pts, n (%) | 79 (90.8) | 26 | 39 | 14 | 0.84 |
| aPL in 84 pts, n (%) | 56 (66.7) | 14 | 29 | 13 | 0.47 |
| Anti-ENA in 69 pts, n (%) | 35 (50.7) | 8 | 21 | 6 | 0.93 |
| Prednisone dosage, mg/day | 8.8 (6.8) | 9.73 (8.07) | 8.68 (6.8) | 7.5 (4.1) | 0.82 |
| Antimalarial use*, n (%) | 16 (21.6) | 8 | 4 | 4 | 0.69 |
| Immunosuppression†, n (%) | 44 (50.5) | 5 | 20 | 8 | 0.053 |
| MMF | 18 | 2 | 12 | 4 | 0.13 |
| AZA | 11 | 2 | 5 | 4 | 0.30 |
| CNI | 3 | 0 | 3 | 0 | 0.84 |
| CYC | 1 | 1 | 0 | 0 | 0.81 |
| Class ISN/RPS2003‡, n | |||||
| I | 1 | 0 | 0 | 1 | 0.15 |
| II | 3 | 0 | 2 | 1 | 0.12 |
| III | 9 | 0 | 6 | 3 | 0.28 |
| IV | 42 | 21 | 15 | 6 | <0.001 |
| V | 14 | 0 | 10 | 4 | 0.09 |
| Mixed | 20 | 6 | 11 | 3 | 0.91 |
| AI | 4.7 (3.8) | 5.9 (3.7) | 4.5 (3.8) | 3.8 (3.7) | 0.4 |
| CI | 4.0 (2.4) | 6.1 (2.6) | 2.9 (1.5) | 3.9 (2.2) | <0.001 |
| Time between first and second biopsy (years) | 6.7 (4.9) | 8.2 (5.1) | 6.9 (4.6) | 3.5 (4.1) | <0.001 |
| Time from repeated biopsy to end of follow-up (years) | 10.3 (9.8) | 8.9 (9.4) | 10.4 (9.1) | 12.1 (12.4) | 0.61 |
| ESKD, n (%) | 25 (27.2) | 18 (60.7) | 6 (13) | 2 (11) | <0.001 |
Comparison between continuous variables: one way ANOVA with Bonferroni correction; comparison between proportions: χ² test.
*Data available for 74 patients.
†Data and referred percentages are calculated 87 patients.
‡Data for 89 patients.
eGFR glomerular filtration rate; aPL antiphospholipid antibodies; AI, activity index; ANOVA, analysis of variance; anti-dsDNA, antibodies antidouble stranded DNA; anti-ENA, antiextractable nuclear antigens antibodies; AZA, azathioprine; CI, chronicity index; CNI, calcineurin inhibitors; CYC, cyclophosphamide; ESKD, end-stage kidney disease; ISN/RPS, International Society of Nephrology/Renal Pathology Society; MMF, mycophenolate mofetil; pts, patients; SCr, serum creatinine.