Table 2. Baseline characteristics of study population by the RDW groups.
| Variable | All Subjects | Low RDW (RDW< = 14.9%) | High RDW (RDW>14.9%) | p-value |
|---|---|---|---|---|
| (n = 1075) | (n = 722) | (n = 353) | ||
| sex (% male) | 605(56.28%) | 417(57.76%) | 188(53.26%) | 0.183 |
| Age (years) | 64.2±12.35 | 63.44±12.71 | 65.77±11.45 | 0.003 |
| BMI (kg/ m2) | 25.17±4.15 | 25.27±4.19 | 24.96±4.08 | 0.245 |
| Current smoker | 277(25.77%) | 185(25.62%) | 92(26.06%) | 0.877 |
| Medication prescription | ||||
| ACE inhibitor/ARB | 704(65.49%) | 467(64.68%) | 237(67.14%) | 0.426 |
| Vitamin B12 (cyanocobalamin) | 224(20.84%) | 150(20.78%) | 74(20.96%) | 0.943 |
| Iron preparations | 169(15.72%) | 82(11.36%) | 87(24.65%) | <0.001 |
| Folic acid | 214(19.91%) | 124(17.17%) | 90(25.5%) | 0.001 |
| Calcium channel blocker | 662(61.58%) | 446(61.77%) | 216(61.19%) | 0.854 |
| Erythropoiesis stimulating agents | 209(19.44%) | 114(15.79%) | 95(26.91%) | <0.001 |
| Phosphate binder | 88(8.19%) | 49(6.79%) | 39(11.05%) | 0.024 |
| Comorbid conditions | ||||
| Cancer | 102(9.49%) | 60(8.31%) | 42(11.9%) | 0.076 |
| Cerebrovascular disease | 159(14.79%) | 103(14.27%) | 56(15.86%) | 0.522 |
| Chronic lung disease | 158(14.7%) | 99(13.71%) | 59(16.71%) | 0.200 |
| Congestive heart failure | 122(11.35%) | 65(9%) | 57(16.15%) | 0.001 |
| Coronary artery disease | 269(25.02%) | 166(22.99%) | 103(29.18%) | 0.028 |
| Dementia | 29(2.7%) | 20(2.77%) | 9(2.55%) | 1.000 |
| Diabetes mellitus | 531(49.4%) | 342(47.37%) | 189(53.54%) | 0.057 |
| Hyperlipidemia | 421(39.16%) | 286(39.61%) | 135(38.24%) | 0.666 |
| Hypertension | 782(72.74%) | 534(73.96%) | 248(70.25%) | 0.200 |
| Liver cirrhosis | 17(1.58%) | 8(1.11%) | 9(2.55%) | 0.075 |
| Peripheral artery disease | 15(1.4%) | 12(1.66%) | 3(0.85%) | 0.409 |
| Laboratory data | ||||
| Creatinine (mg/dL) | 3.54±2.26 | 3.39±2.2 | 3.85±2.33 | 0.002 |
| eGFR (ml/min per 1.73 m2) | 22.85±12.69 | 23.94±12.91 | 20.64±11.94 | <0.001 |
| Hemoglobin (g/dL) | 10.64±2.14 | 11.03±2.08 | 9.83±2.04 | <0.001 |
| Mean corpuscular volume (fL) | 90.3±7.53 | 91.64±5.33 | 87.57±10.18 | <0.001 |
| Platelet count (x103/μL) | 227.27±75.81 | 226.60±67.79 | 228.64±90.10 | 0.707 |
| WBC count (x103μL) | 7.49±2.50 | 7.35±2.39 | 7.77±2.70 | 0.015 |
| Albumin (g/dL) | 3.7±0.65 | 3.8±0.61 | 3.47±0.68 | <0.001 |
| BUN (mg/dL) | 46.1±23.14 | 43.28±22.02 | 51.85±24.3 | <0.001 |
| Cholesterol (mg/dL) | 184.91±53.72 | 186.52±48.32 | 181.6±63.3 | 0.197 |
| Triglyceride (mg/dL) | 153.3±104.53 | 157.04±101.99 | 145.65±109.3 | 0.094 |
| Ca (mg/dL) | 8.78±0.67 | 8.83±0.63 | 8.68±0.75 | 0.001 |
| Phosphate (mg/dl) | 4.2±1.11 | 4.14±1.08 | 4.34±1.16 | 0.007 |
| Calcium phosphate product (mg2/dL2) | 36.62±8.96 | 36.24±8.59 | 37.42±9.63 | 0.051 |
| Uric acid (mg/dL) | 7.98±1.82 | 7.91±1.8 | 8.12±1.88 | 0.085 |
| Proteinuria (mg/day) | 1713.56±2485.78 | 1521.54±2130.34 | 2169.6±3133.9 | 0.008 |
Values are expressed as mean ± SD or number (percentage).
CKD, chronic kidney disease; eGFR, estimated glomerular filtration rate; BMI, body mass index; ACE inhibitor, angiotensin-converting enzyme inhibitor; ARB, angiotensin II receptor blocker.