Demographics and characteristics of patients undergoing clinically indicated kidney biopsy
| All patients, n=475 | Without AE, n=434 | With related AE, n=34 | With unrelated AE, n=7 | |
| Age, median (IQR) | 34 (26–44), n=441 | 34 (26–44), n=400 | 34.5 (26–44) | 42 (23–45) |
| Sex, n (%) | ||||
| Female | 390 (82.1) | 352 (81.1) | 32 (94.1) | 6 (85.7) |
| Male | 68 (14.3) | 65 (15.0) | 2 (5.9) | 1 (14.3) |
| Unknown | 17 (3.6%) | 17 (3.9) | 0 (0.0) | 0 (0.0) |
| Race, n (%) | ||||
| Asian | 70 (14.7) | 60 (13.8) | 9 (26.5) | 1 (14.3) |
| Black | 192 (40.4) | 179 (41.2) | 12 (35.3) | 1 (14.3) |
| White | 152 (32.0) | 139 (32.0) | 10 (29.4) | 3 (42.9) |
| Other/unknown | 61 (12.8) | 56 (12.9) | 3 (8.8) | 2 (28.6) |
| Ethnicity, n (%) | ||||
| Hispanic/Latino | 125 (26.3) | 116 (26.7) | 6 (17.6) | 3 (42.9) |
| Not Hispanic/Latino | 331 (69.7) | 299 (68.9) | 28 (82.4) | 4 (57.1) |
| Unknown | 19 (4.0) | 19 (4.4) | 0 (0.0) | 0 (0.0) |
| Diagnosis, n (%) | ||||
| Class I | 8 (1.7) | 8 (1.8) | 0 (0.0) | 0 (0.0) |
| Class II | 30 (6.3) | 28 (6.5) | 2 (5.9) | 0 (0.0) |
| Class III | 76 (16.0) | 74 (17.1) | 2 (5.9) | 0 (0.0) |
| Class IV | 62 (13.1) | 57 (13.1) | 5 (14.7) | 0 (0.0) |
| Class V | 105 (22.1) | 95 (21.9) | 10 (29.4) | 0 (0.0) |
| Class VI | 17 (3.6) | 16 (3.7) | 1 (2.9) | 0 (0.0) |
| Class mixed (III/V, IV/V) | 123 (25.9) | 111 (25.6) | 8 (23.5) | 4 (57.1) |
| Unexpected mixed (I/VI, II/VI) | 5 (1.1) | 1 (0.2) | 1 (2.9) | 3 (42.9) |
| Other | 44 (9.3) | 42 (9.7) | 2 (5.9) | 0 (0.0) |
| Insufficient tissue for diagnosis | 5 (1.1) | 2 (0.5) | 3 (8.8) | 0 (0.0) |
| Activity index, median (IQR) | 4 (1–8), n=266 | 4 (1–8), n=242 | 6 (0–9), n=18 | 4 (1–8), n=6 |
| Chronicity index, median (IQR) | 3 (1–5), n=269 | 3 (1–5), n=244 | 5 (0–5), n=19 | 2 (1–4), n=6 |
| History of aPL antibodies, n (%) | n=383 | n=347 | n=29 | n=7 |
| aPL by ACR criteria | 123 (32.1) | 112 (32.3) | 11 (37.9) | 0 (0.0) |
| Biopsy history, n (%) | n=419 | n=379 | n=33 | |
| First biopsy | 157 (37.5) | 140 (36.9) | 14 (42.4) | 3 (42.9) |
| Previously biopsied | 262 (62.5) | 239 (63.1) | 19 (57.6) | 4 (57.1) |
| Medication at biopsy, n (%) | n=419 | n=381 | n=31 | n=7 |
| Hydroxychloroquine | 354 (84.5) | 317 (83.2) | 31 (100.0) | 6 (85.7) |
| Prednisone | 254 (60.6) | 231 (60.6) | 19 (61.3) | 4 (57.1) |
| Azathioprine | 33 (7.9) | 27 (7.1) | 4 (12.9) | 2 (28.6) |
| Mycophenolate mofetil/mycophenolic acid | 181 (43.2) | 168 (44.1) | 11 (35.5) | 2 (28.6) |
| Pulse steroids (500 mg or 1000 mg) | 18 (4.3) | 14 (3.7) | 3 (9.7) | 1 (14.3) |
| Cytoxan | 7 (1.7) | 7 (1.8) | 0 (0.0) | 0 (0.0) |
| Tacrolimus | 23 (5.5) | 21 (5.5) | 1 (3.2) | 1 (14.3) |
| Clinical laboratory values | ||||
| Random UPCR, median (IQR) | 1.9 (1.0–3.7), n=419 | 1.9 (1.1–3.7), n=382,mean=2.86 | 2.2 (1.3–3.8), n=30, mean=3.79 | 3.0 (1.4–9.5), mean=5.37 |
| Platelet count (cells x 109/L), median (IQR) | 237 (187–297), n=439 | 240 (192–301), n=399, mean=252 | 220 (178–271), n=33, mean=231 | 207 (145–256), mean=207 |
| Platelet count <100 cells x 109/L, n (%) | 10 (3) | 2 (6) | 0 (0) | |
| Serum creatinine, median (IQR) | 0.9 (0.7–1.4), n=421 | 0.9 (0.7–1.4), n=383, mean=1.21 | 0.9 (0.7–1.5), n=31, mean=1.14 | 0.8 (0.5–2.3), mean=1.28 |
| Research biopsy length (mm), median (IQR) | 7 (5–11), n=363 | 7.3 (5–10), n=336, mean=8.58 | 7.5 (5–13), n=22, mean=8.39 | 5 (4.5–9.5), n=5, mean=6.6 |
| Number of passes (NYU only), median (IQR) | 3 (2–3), n=153 | 3 (2–3), n=140, mean=3.07 | 3 (3–4), n=9, mean=3.44 | 3 (2.5–3), n=4, mean=2.75 |
ACR, American College of Rheumatology; AE, adverse event; aPL, antiphospholipid; NYU, New York University; UPCR, urine protein to creatinine ratio.