Table 3.
Baseline characteristics of patients with CKD and MG who underwent a kidney biopsy compared with those that did not from 2017 to 2018
| Characteristics | Overall (n=596) | Kidney Biopsy (n=62) | No Kidney Biopsy (n=534) | OR (95% CI) | P Value |
|---|---|---|---|---|---|
| Age (yr) | 70.5±12.6 | 65.7±9.5 | 71.00±12.8 | 0.97 (0.95 to 0.99) | 0.003 |
| Male | 401 (67.3%) | 45 (72.6%) | 356 (66.7%) | 1.32 (0.74 to 2.38) | 0.34 |
| White | 580 (97.3) | 56 (90.3%) | 524 (98.1%) | 0.18 (0.06 to 0.51) | 0.004 |
| DM | 194 (32.6%) | 17 (27.4%) | 177 (33.2%) | 0.76 (0.41 to 1.35) | 0.36 |
| Hypertension | 516 (86.6%) | 56 (90.3%) | 460 (86.1%) | 1.50 (0.62 to 3.61) | 0.34 |
| Congestive heart failure | 182 (30.5%) | 11 (17.7%) | 171 (32.0%) | 0.46 (0.23 to 0.90) | 0.02 |
| CCI | 3.76±2.4 | 3.3±2.03 | 3.8±2.4 | 0.90 (0.80 to 1.02) | 0.08 |
| CKD | |||||
| Stage 1 | 28 (4.7%) | 1 (1.6%) | 27 (5.1%) | Reference | Reference |
| Stage 2 | 96 (16.2%) | 7 (11.5%) | 89 (16.7%) | 2.12 (0.25 to 18.03) | 0.49 |
| Stage 3 | 362 (60.8%) | 30 (49.2%) | 332 (62.2%) | 2.44 (0.32 to 18.59) | 0.39 |
| Stage 4 | 84 (14.1%) | 16 (26.2%) | 68 (12.7%) | 6.35 (0.80 to 50.29) | 0.08 |
| Stage 5a | 25 (4.2%) | 7 (11.5%) | 18 (3.4%) | 10.50 (1.19 to 92.75) | 0.03 |
| Serum studies | |||||
| Creatinine (mg/dl) | 1.6±0.9 | 2.20±1.3 | 1.60±0.8 | 1.70 (1.36 to 2.14) | <0.001 |
| eGFR (ml/min per 1.73 m2) | 47.5±20.3 | 37.6±20.5 | 48.7±20.0 | 0.96 (0.94 to 0.99) | 0.006 |
| Urinary studies | |||||
| Urinary protein (g/d) | 0.39 (0.18 to 1.08) | 1.67 (0.28 to 4.05) | 0.67 (0.17 to 0.86) | 1.19 (1.10 to 1.29) | <0.001 |
| Proteinuria ≥1.5 g/d | 96 (19.1%) | 33 (53.2%) | 63 (14.3%) | 6.83 (3.88 to 12.02) | <0.001 |
| NRP | 51 (10.1%) | 18 (29.0%) | 33 (7.5%) | 5.05 (2.63 to 9.72) | <0.001 |
| Hematuria | 1076 (21.4%) | 21 (35.0%) | 85 (19.5%) | 2.22 (1.24 to 3.98) | 0.009 |
| Hematologic studies | |||||
| Clonality | |||||
| Monoclonal | 571 (95.8%) | 59 (95.2%) | 512 (95.9%) | Reference | Reference |
| Biclonal | 25 (4.2%) | 3 (4.8%) | 22 (4.1%) | 1.18 (0.27 to 3.55) | 0.79 |
| IgG heavy chain | 339 (69.0%) | 35 (72.9%) | 304 (68.5%) | 1.24 (0.64 to 2.42) | 0.52 |
| M-protein spike (g/dl) | 1.0±0.6 | 1.0±0.5 | 1.0±0.6 | 1.04 (0.45 to 2.36) | 0.94 |
| κ FLC (mg/dl) | 3.7 (2.01 to 8.56) | 4.81 (2.48 to 10.14) | 3.5 (1.97 to 7.97) | 1.01 (0.99 to 1.02) | 0.26 |
| λ FLC (mg/dl) | 2.8 (1.52 to 5.81) | 2.91 (1.64 to 7.86) | 2.80 (1.51 to 5.62) | 1.00 (0.99 to 1.01) | >0.99 |
| Affected/unaffected FLC ratio | 2.24 (1.20 to 5.56) | 3.14 (1.26 to 6.87) | 2.14 (1.19 to 5.45) | 1.00 (0.99 to 1.01) | 0.25 |
| Abnormal FLC ratio | 197 (41.9%) | 29 (50%) | 168 (40.8%) | 1.45 (0.84 to 2.52) | 0.19 |
Values for continuous variables are described as mean±SD or median (IQR) depending on the distribution, and for categoric variables described as count (%). NRP, nephrotic-range proteinuria.
a
Stage 5 patients were not on dialysis.