Table 1.
Characteristics of patients with monoclonal gammopathy who underwent kidney biopsy from 1999 to 2020 in the Peking University First Hospital
| Characteristics | Overall, n=687 | Monoclonal Gammopathy of Renal Significance Lesions, n=261 | Nonmonoclonal Gammopathy of Renal Significance Lesions, n=426 | P Value |
|---|---|---|---|---|
| Age, yr | 56 (49–66) | 58 (51–66) | 56 (47–66) | 0.28 |
| Men, n (%) | 457 (67) | 162 (62) | 295 (69) | 0.05 |
| Hypertension, n (%) | 439 (64) | 145 (56) | 294 (69) | <0.001 |
| Diabetes mellitus, n (%) | 154 (22) | 38 (15) | 116 (27) | <0.001 |
| Serum studies | ||||
| Albumin, g/dl | 2.9 (2.2–3.5) | 2.8 (2.2–3.3) | 3.0 (2.3–3.7) | 0.006 |
| Albumin <3.0 g/dl, n (%) | 381 (55) | 159 (61) | 222 (52) | 0.02 |
| Hemoglobin, g/dl | 12.0 (10.2–13.8) | 12.1 (10.2–13.9) | 12.0 (10.2–13.6) | 0.36 |
| Creatinine, mg/dl | 1.8 (0.8–2.1) | 1.8 (0.8–2.2) | 1.8 (0.8–2.0) | 0.80 |
| eGFR, ml/min per 1.73 m2 | 63 (32–91) | 60 (28–89) | 64 (35–92) | 0.25 |
| Complement 3, mg/dl | 88±27 (600/687) | 85 (65–105, 235/261) | 89±25 (365/426) | 0.02 |
| Complement 3 <60, mg/dl, n (%) | 91/600 (15) | 44/235 (19) | 47/365 (13) | 0.05 |
| Complement 4, mg/dl | 25 (18–29, 591/687) | 24 (17–30, 230/261) | 25 (19–29, 361/426) | 0.61 |
| Urinary studies | ||||
| Urinary protein, g/d | 4.9 (1.5–6.5) | 5.0 (2.3–6.6) | 4.9 (1.2–6.5) | 0.01 |
| Proteinuria ≥1.5 g/d, n (%) | 511 (74) | 212 (81) | 299 (70) | 0.001 |
| Hematuria | 371 (54) | 117 (45) | 254 (60) | <0.001 |
| Hematologic studies | ||||
| κ-free light chain, mg/L | 106 (20–68, 235/687) | 167 (15–133, 103/261) | 57 (21–58, 132/426) | 0.81 |
| λ-free light chain, mg/L | 98 (26–93, 235/687) | 130 (24–114, 103/261) | 73 (27–75, 132/426) | 0.19 |
| Free light chain-κ/λ ratio | 7.6 (0.4–1.6, 235/687) | 16.0 (0.2–2.9, 103/261) | 1.1 (0.6–1.2, 132/426) | 0.32 |
| Abnormal free light chain ratio | 95/235 (40) | 66/103 (64) | 29/132 (22) | <0.001 |
| Received bone marrow biopsy, n (%) | 521 (76) | 230 (88) | 291 (68) | <0.001 |
| Plasma cell percentage | 2.1 (0.5–2.5, 518/687) | 2.9 (1.0–4.0, 230/518) | 1.5 (0.5–2.0, 288/518) | <0.001 |
| Plasma cell percentage ≥10%, n (%) | 10/518 (2) | 8/230 (4) | 2/288 (1) | 0.02 |
| Abnormal bone marrow biopsy specimen, n (%) | 232/359 (65) | 121/146 (83) | 111/213 (52) | <0.001 |
Values for continuous variables are described as mean ± SD or median (interquartile range) depending on the distribution, and for categoric variables, they are described as count (percentage).