TABLE 1.
Baseline characteristics of the study populations according to the RDW level.
| Characteristics | Total (n = 523) | RDW group |
P-value | |
| RDW ≤ 14.5% (n = 463) | RDW > 14.5% (n = 60) | |||
| Demographics | ||||
| Age (years) | 57 (44, 69) | 56 (43, 69) | 60 (48, 73) | 0.12 |
| Sex (n%) | 0.12 | |||
| Male | 276 (52.77) | 250 (54.00) | 26 (43.33) | |
| Female | 247 (47.23) | 213 (46.00) | 34 (56.67) | |
| Cause of renal disease (n%) | 0.59 | |||
| Glomerulonephritis | 125 (23.90) | 111 (23.97) | 14 (23.33) | |
| Diabetic nephropathy | 88 (16.83) | 80 (17.28) | 8 (13.33) | |
| Hypertensive renal disease | 130 (24.86) | 112(24.19) | 18 (30.00) | |
| Tubulointerstitial disease | 33 (6.31) | 32 (6.91) | 1 (1.67) | |
| Polycystic kidney disease | 10 (1.91) | 8 (1.73) | 2 (3.33) | |
| Pyelonephritis | 3 (0.57) | 3 (0.65) | 0 (0.00) | |
| Other | 36 (6.88) | 30 (6.48) | 6 (10.00) | |
| Unknown | 98 (18.74) | 87 (18.79) | 11 (18.33) | |
| Clinical | ||||
| Hypertension (n%) | 151 (28.87) | 132 (28.51) | 19 (31.67) | 0.61 |
| Diabetes (n%) | 238 (45.51) | 213 (46.00) | 25 (41.67) | 0.52 |
| Anemia (n%) | <0.001 | |||
| Mild | 192 (36.71) | 153 (33.05) | 39 (65.00) | |
| Moderate | 8 (1.53) | 4 (0.86) | 4 (6.67) | |
| CKD stages (n%) | <0.001 | |||
| CKD stage 1 | 9 (1.72) | 9 (1.94) | 0 (0.00) | |
| CKD stage 2 | 47 (8.99) | 44 (9.50) | 3 (5.00) | |
| CKD stage 3 | 293 (56.02) | 270 (58.32) | 23 (38.33) | |
| CKD stage 4 | 174 (33.27) | 140 (30.24) | 34 (56.67) | |
| Laboratory | ||||
| WBC (× 1012/L) | 6.40 (5.40, 7.60) | 6.33 (5.40, 7.60) | 6.41 (5.33, 7.55) | 0.96 |
| RBC (× 1012/L) | 4.19 ± 0.64 | 4.22 ± 0.63 | 3.92 ± 0.67 | <0.001 |
| Hemoglobin (g/L) | 129.6 ± 19.7 | 131.3 ± 19.4 | 116.1 ± 17.0 | <0.001 |
| MCV (fl) | 89.96 ± 6.00 | 90.23 ± 5.80 | 87.83 ± 7.06 | 0.01 |
| RDW (%) | 13.2 (12.6, 13.8) | 13.1 (12.6, 13.6) | 15.1 (14.8, 15.7) | <0.001 |
| Lymphocyte (%) | 27.39 ± 8.06 | 27.77 ± 7.88 | 24.44 ± 8.79 | 0.002 |
| Albumin (g/dL) | 43.0 (40.8, 45.1) | 43.1 (41.0, 45.2) | 41.9 (38.1, 43.6) | <0.001 |
| Blood glucose (mmol/L) | 5.83 ± 1.36 | 5.80 ± 1.33 | 6.06 ± 1.54 | 0.16 |
| Bicarbonate (mmol/L) | 24.60 ± 2.93 | 24.75 ± 2.91 | 23.43 ± 2.78 | 0.001 |
| Calcium (mmol/L) | 2.31 (2.24, 2.38) | 2.32 (2.24, 2.38) | 2.26 (2.18, 2.34) | <0.001 |
| Phosphorus (mmol/L) | 1.18 (1.04, 1.31) | 1.17 (1.03, 1.31) | 1.23 (1.10, 1.32) | 0.17 |
| Serum iron (μmol/L) | 14.99 (13.05, 16.80) | 15.18 (13.20, 16.90) | 13.41 (11.15, 15.61) | 0.002 |
| eGFR (ml/min/1.73 m2) | 37.30 (26.86, 49.01) | 38.27 (27.85, 49.57) | 28.40 (22.36, 38.93) | <0.001 |
| UACR (mg/g) | 324.71 (128.67, 679.79) | 311.43 (117.54, 621.77) | 525.70 (279.68, 975.51) | 0.004 |
| 24-h urine protein (g/24 h) | 0.74 (0.21, 1.45) | 0.72 (0.19, 1.39) | 1.04 (0.59, 1.77) | 0.02 |
| Uric acid (μmol/L) | 415.3 ± 93.9 | 415.9 ± 94.8 | 410.5 ± 87.4 | 0.68 |
| TG (mmol/L) | 1.55 (1.11, 2.24) | 1.58 (1.11, 2.27) | 1.40 (1.04, 1.89) | 0.08 |
| TCHO (mmol/L) | 4.55 (3.86, 5.31) | 4.57 (3.92, 5.38) | 4.08 (3.41, 4.84) | 0.003 |
| LDL-C (mmol/L) | 2.55 (2.01, 3.09) | 2.60 (2.07, 3.14) | 2.08 (1.71, 2.77) | <0.001 |
| Treatment | ||||
| Iron supplements (n%) | 219 (41.87) | 176 (38.01) | 43 (71.67) | <0.001 |
| EPO-stimulating agents (n%) | 143 (27.34) | 114 (24.62) | 29 (48.33) | <0.001 |
| ACEI or ARB (n%) | 402 (77.91) | 355 (77.85) | 47 (78.33) | 0.93 |
| Alpha-blockers (n%) | 145 (28.10) | 122 (26.75) | 23 (38.33) | 0.06 |
| Beta-blockers (n%) | 124 (24.03) | 102 (22.37) | 22 (36.67) | 0.01 |
| Calcium-channel blockers (n%) | 379 (73.45) | 326 (71.49) | 53 (88.33) | 0.006 |
| Loop diuretics (n%) | 188 (36.43) | 160 (35.09) | 28 (46.67) | 0.08 |
Data are expressed as mean ± SD, median value (interquartile range) or n (%).
ACEI, angiotensin converting–enzyme inhibitors; ARB, angiotensin II–receptor blockers; CKD, chronic kidney disease; eGFR, estimated glomerular filtration rate; EPO, erythropoietin; LDL-C, low-density lipoprotein cholesterol; MCV, mean corpuscular volume; RBC, red blood cell; RDW, red blood cell distribution width; SD, standard deviation; TCHO, total cholesterol; TG, triglyceride; UACR, urinary albumin-creatinine ratio; WBC, white blood cell.