Clinical/histological features, therapy at first and second kidney biopsy and patient/kidney outcomes in all patients and in those who received a first and a second kidney biopsy for proteinuric flare, nephritic flare or protocol biopsy
| Variables | All pts (n=61) | Proteinuric flare (n=22) | Nephritic flare (n=25) | Protocol biopsy (n=14) | ||||
| Data at 1st KB | Data at 2nd KB | Data at 1st KB | Data at 2nd KB | Data at 1st KB | Data at 2nd KB | Data at 1st KB | Data at 2nd KB | |
| Male/Female, n* of pts (%) | 6 (10)/55 (90) | 2 (9)/20 (91) | 4 (16)/21 (84) | 0/14 (100) | ||||
| Age at kidney biopsy, years | 28 (22–36) | 34 (28–45) | 29 (22–32) | 34 (28–44) | 27 (21–35) | 34 (28–47) | 28 (27–48) | 33 (29–47) |
| Serum creatinine, mg/dL | 1.1 (0.8–1.6) | 1.1 (0.9–1.6) | 1 (0.7–1.3) | 0.9 (0.7–1) | 1.2 (1–1.6) | 1.6 (1.5–2.4) | 1.3 (1–1.6) | 1 (0.9–1.1) |
| eGFR, mL/min/1.73 m2 | 66 (44–99.5) | 66.5 (42–87) | 79 (59–115) | 106 (75–112) | 65 (43–89) | 37 (28–49) | 57 (42–66) | 68 (58–86) |
| Proteinuria, g/die | 3.3 (1.8–5.6) | 2.4(1-5) | 3.4 (1.4–5.7) | 2.7 (2–4.5) | 4.4(3-6) | 4.1 (1.9–6.8) | 2.9 (1.8–3.9) | 0.2 (0.2–0.4) |
| Urinary erythrocytes,n*/HPF | 20 (7–40) | 5 (0–16) | 13 (5–21) | 5 (0–13) | 34 (12–52) | 17.5 (1–40) | 40 (14–40) | 3 (1–5) |
| Serum C3, mg/dL† | 50 (40–67) | 80 (50–95) | 54 (42–66) | 69 (56–97) | 50 (36–73) | 61 (42–90) | 50 (45–59) | 97 (85–112) |
| Serum C4, mg/dL‡ | 7 (5–13.5) | 13.5(10-18) | 11.5(5-15) | 11(9-15) | 5.5 (5–9) | 13 (9.5–17) | 7 (5–11) | 17 (16–19) |
| Arterial hypertension, n*(%) | 32 (52) | 31 (51) | 11 (50) | 10 (45.5) | 11(44) | 17 (68) | 10 (71) | 4 (28) |
| Months from 1* to 2* KB | 49 (27–96) | 61 (36–102) | 79 (28–112) | 27 (26.5–28) | ||||
| Induction therapy, n* pts(%) | ||||||||
| Methylprednisolone pulses IST induction Cyclophosphamide na | 38 (70) 39 (72) 26 (48) 7 | 28 (49) 23 (40) 13 (23) 4 | 11 (55) 14 (70) 10 (50) 2 | 11 (52) 9 (43) 5 (24) 1 | 17 (81) 13 (62) 8 (38)¶ 4 | 16 (69.5) 13 (56.5) 8 (35) 2 | 10 (77) 12 (92)§ 8 (61) 1 | 1 (7.7) 1 (7.7) 0 1 |
| Maintenance therapy, n* (%) MMF/AZA/CsA, % na | 28 (51) 9/34.5/11 6 | 33 (58) 30/26/14 4 | 5 (26) –/26/– 3 | 11 (52) 38/9/14 1 | 10 (45) 14/27/4.5 3 | 12 (53) 22/35/4 2 | 13 (93) 14/57/36 – | 10 (77) 31/38/31 1 |
| Follow-up, years | 23 (17.5–32) | 30 (20.8–34.5) | 21.6 (13–30) | 22 (21–28) | ||||
| KFI, n* pts (%) | 25 (41%)** | 6 (27%) | 16 (64%)†† | 3 (21%) | ||||
| ESRD, n* pts (%) | 12 (20%) | 4 (18%) | 7 (28%) | 1 (7%) | ||||
| Death, n* pts (%) | 14 (23%) | 6 (27%) | 7 (28%) | 1 (7%) | ||||
| Histological class, n* | ||||||||
| I/II/III/IV/V Mixed classes | –/–/7/47/7 7 | 1/6/12/36/6 13 | –/–/2/15/5‡‡ 2 | –/1/6/12/3 8 | –/–/3/21/1 2 | –/1/3/20/1 2 | –/–/2/11/1 3 | 1/4/3/4/2 3 |
| Activity index | 7 (5–10) | 3 (0–6) | 7.5 (6–10) | 2.5 (0.25–5) | 7.5 (5–10) | 5 (3–9) | 6 (4–10) | 1 (0–2) |
| Chronicity index | 1 (0–3) | 4 (2–6) | 1 (0–2) | 4 (2–4) | 1 (0–2) | 5 (2–7) | 3 (2–4)§§/¶¶ | 3 (2–6) |
| Increase in CI from 1st and 2nd KB | 2 (0–4) | 2 (0–2.75) | 3 (2–6)*** | 0.5 (0–2) | ||||
| N* pts (%) with no increase of CI between first and second KB | 17 (28%)††† | 7 (32%) | 3 (12%)‡‡‡ | 7 (50%) | ||||
*1 data missing.
†Normal values 90–180 mg/dL.
‡Normal values 10–40 mg/dL.
§P=0.053; refers to the comparison of the frequencies of induction therapy in protocol biopsy group vs nephritic flare and proteinuric flare groups.
¶P=0.028; refers to the comparison of the frequencies of cyclophosphamide therapy in nephritic flare group vs proteinuric flare and protocol biopsy.
**P=0.009; refers to comparison of the frequencies of KFI between the three different groups.
††P=0.001; refers to the comparison of the frequencies of KFI in nephritic flare group vs proteinuric flare and protocol biopsy groups.
‡‡P=0.038; refers to the comparison of incidences of class V NL in proteinuric flare group vs nephritic flare and protocol biopsy groups.
§§P=0.002; refers to the comparison between proteinuric flare and protocol biopsy group.
¶¶P=0.001; refers to the comparison between proteinuric flare and nephitic biopsy group.
***P=0.001; refers to the comparison of nephritic flare group vs proteinuric flare and protocol biopsy groups.
†††P=0.035; refers to comparison between the three different groups.
‡‡‡P=0.021; refers to the comparison of nephritic flare group vs proteinuric flare and protocol biopsy groups.
AZA, Azathioprine; CsA, Ciclosporin; eGFR, estimated glomerular filtration rate; ESRD, End Stage Renal Disease; HPF, High-power field; IST, Immunosuppressive Therapy; KB, kidney biopsy; KFI, kidney function impairment; MMF, mycophenolate mofetil.