Table 1.
Comparison of clinical features of patients with and without C3 deposition
| Variable | All (N = 142) | C3 positive (n = 56) | C3 negative (n = 86) | P value |
|---|---|---|---|---|
| Age, yr | 73.0 (65.0–80.0) | 72.5 (64.3–80.0) | 73.0 (66.5–79.3) | 0.87 |
| Male, n (%) | 55 (38.7) | 26 (46.4) | 29 (33.7) | 0.13 |
| AAV subtype (MPA/GPA/EGPA/RLV, n) | 124/14/1/3 | 50/4/1/1 | 74/10/0/2 | 0.51 |
| MPO-ANCA positive, n (%)a | 128 (90.1) | 53 (94.6) | 75 (87.2) | 0.15 |
| PR3-ANCA positive, n (%)a | 20 (14.1) | 4 (7.1) | 16 (18.6) | 0.06 |
| Lung involvement, n (%) | 85 (59.9) | 32 (57.1) | 53 (61.6) | 0.59 |
| Dialysis at onset, n (%) | 34 (23.9) | 17 (30.4) | 17 (19.8) | 0.15 |
| BMI (kg/m2) | 21.7 (19.3–23.6) | 22.1 (19.8–23.8) | 21.7 (19.1–23.4) | 0.56 |
| MAP (mm Hg) | 96.0 (86.7–105.3) | 96.7 (87.4–108.8) | 95.2 (86.5–104.7) | 0.31 |
| Hypertension, n (%) | 85 (59.9) | 34 (60.7) | 51 (59.3) | 0.87 |
| Immunosuppressors, n (%) | 0.11 | |||
| PSL | 84 (59.2) | 34 (60.7) | 50 (58.1) | — |
| PSL + RTX | 25 (17.6) | 12 (21.4) | 13 (15.1) | — |
| PSL + IVCY | 16 (11.3) | 2 (3.6) | 14 (16.3) | — |
| Others | 17 (12.0) | 8 (14.3) | 9 (10.5) | — |
| eGFR (ml/min per 1.73 m2) | 17.9 (8.0–39.0) | 13.6 (8.0–35.7) | 21.4 (8.8–42.6) | 0.24 |
| 1-year eGFR (ml/min per 1.73 m2)b | 23.5 (0.0–40.3) | 22.9 (0.0–33.9) | 25.0 (10.4–43.8) | 0.17 |
| UPE (g/d) | 1.2 (0.5–2.2) | 1.3 (0.5–2.7) | 1.2 (0.5–2.0) | 0.37 |
| U-RBC (/HPF), n (%) | 0.28 | |||
| <0 to 5 | 11 (7.7) | 2 (3.6) | 9 (10.5) | — |
| <50 | 50 (35.2) | 19 (33.9) | 31 (36.0) | — |
| ≥50 | 27 (19.0) | 14 (25.0) | 13 (15.1) | — |
| ≥100 | 54 (38.0) | 21 (37.5) | 33 (38.4) | — |
| WBC (μl) | 8600 (6650–11,725) | 7600 (5375–11,675) | 9600 (7375–11,950) | 0.01 |
| Hb (mg/dl) | 9.6 (8.4–11.1) | 9.5 (8.2–10.9) | 9.7 (8.5–11.3) | 0.51 |
| Alb (mg/dl) | 2.8 (2.3–3.3) | 2.9 (2.1–3.5) | 2.8 (2.5–3.2) | 0.93 |
| CRP (mg/dl) | 3.9 (0.5–11.3) | 1.5 (0.2–10.9) | 5.0 (1.2–11.6) | 0.049 |
| IgG (mg/dl) | 1574.0 (1284.5–1858.0) | 1531.0 (1283.0–1845.0) | 1601.0 (1295.5–1867.3) | 0.80 |
| IgA (mg/dl) | 315.0 (231.8–389.0) | 319.0 (243.0–389.0) | 310.5 (226.3–396.5) | 0.91 |
| IgM (mg/dl) | 80.0 (54.5–132.0) | 74.0 (51.3–138.5) | 86.5 (58.8–126.0) | 0.50 |
| C3 (mg/dl) | 108.0 (94.0–126.0) | 101.0 (89.0–118.0) | 115.0 (96.5–137.5) | 0.002 |
| C4 (mg/dl) | 30.0 (23.0–36.8) | 28.0 (22.0–35.0) | 31.0 (23.5–38.5) | 0.09 |
| CH50 (U/ml) | 50.5 (41.4–57.4) | 48.6 (39.4–54.6) | 53.3 (43.4–58.3) | 0.04 |
AAV, antineutrophil cytoplasmic antibody–associated vasculitis; Alb, albumin; ANCA, antineutrophil cytoplasmic antibody; BMI, body mass index; CRP, C reactive protein; eGFR, estimated glomerular filtration rate; EGPA, eosinophilic granulomatosis with polyangiitis; GPA, granulomatosis with polyangiitis; Hb, hemoglobin; HPF, high-power field; IQR, interquartile range; IVCY, i.v. cyclophosphamide; MAP, mean arterial pressure; MPA, microscopic polyangiitis; MPO, myeloperoxidase; PR3, proteinase-3; PSL, prednisolone; RLV, renal-limited vasculitis; RTX, rituximab; UPE, urinary protein excretion; U-RBC, urinary red blood cell; WBC, white blood cell.
Values are presented as medians and IQRs or numbers with percentages in parentheses.
A total of 8 dual-positive (both MPO-ANCA and PR3-ANCA) patients were included, and 2 patients were dual negative.
The 1-year eGFR for dialysis-dependent patients was defined as 0 ml/min per 1.73 m2.25