Table 1.
Baseline characteristics of the study population by the median of mean corpuscular volume
| Variables | Total, n=1439 | MCV<90.8, n=717 | MCV≥90.8, n=722 | P Value |
|---|---|---|---|---|
| Age, yr | 64.1±12.2 | 60.9±13.1 | 67.3±10.3 | <0.001 |
| Age category, yr | <0.001 | |||
| <50 | 124 (17.3%) | 51 (7.1%) | 175 (12.2%) | |
| 50–64 | 258 (36%) | 179 (24.8%) | 437 (30.3%) | |
| ≥65 | 335 (46.7%) | 492 (68.1%) | 827 (57.5%) | |
| Sex, % men | 795 (55.3%) | 362 (50.5%) | 433 (59.9%) | <0.001 |
| Educational level | 0.11 | |||
| Illiterate | 309 (21.5%) | 150 (20.9%) | 159 (22%) | |
| Primary school | 691 (48%) | 327 (45.6%) | 364 (50.4%) | |
| Junior high school | 153 (10.6%) | 79 (11.0%) | 74 (10.3%) | |
| Senior high school | 171 (11.9%) | 98 (13.7%) | 73 (10.1%) | |
| Junior college | 48 (3.3%) | 30 (4.2%) | 18 (2.5%) | |
| University and graduate school | 67 (4.7%) | 33 (4.6%) | 34 (4.7%) | |
| Marital status | 0.02 | |||
| Single | 61 (4.2%) | 42 (5.9%) | 19 (2.6%) | |
| Married | 1149 (79.9%) | 566 (78.9%) | 583 (80.8%) | |
| Widowed | 209 (14.5%) | 97 (13.5%) | 112 (15.5%) | |
| Separated | 8 (0.6%) | 4 (0.6%) | 4 (0.6%) | |
| Divorced | 12 (0.8%) | 8 (1.1%) | 4(0.6%) | |
| Causes of CKD | <0.001 | |||
| DM | 536 (37.2%) | 316 (44.1%) | 220 (30.5%) | |
| Hypertension | 356 (24.7%) | 157 (21.9%) | 199 (27.6%) | |
| Chronic GN | 160 (11.1%) | 74 (10.3%) | 86 (11.9%) | |
| BMI, kg/m2 | 24.9±4.0 | 25.3±4.1 | 24.5±4.0 | <0.001 |
| Smoker, % | 0.47 | |||
| Current smoker | 294 (20.4%) | 141 (19.7%) | 153 (21.2%) | |
| Alcohol, % | 0.56 | |||
| Never | 1257 (87.4%) | 633 (88.3%) | 624 (86.4%) | |
| Current | 73 (5.1%) | 33 (4.6%) | 40 (5.5%) | |
| Former | 109 (7.6%) | 51 (7.1%) | 58 (8.0%) | |
| Medication prescription | ||||
| ACE inhibitor/ARB | 910 (63.2%) | 486 (67.8%) | 424 (58.7%) | <0.001 |
| Vitamin B12 (cyanocobalamin) | 295 (20.5) | 132 (18.4) | 163 (22.6) | 0.05 |
| Iron preparations | 212 (14.7) | 128 (17.9) | 84 (11.6) | 0.001 |
| Folic acid | 358 (24.9) | 155 (21.6) | 203 (28.1) | 0.004 |
| Erythropoiesis-stimulating agents | 324 (22.5) | 176 (24.6) | 148 (20.5) | 0.06 |
| Fibrate | 75 (5.2) | 48 (6.7) | 27 (3.7) | 0.01 |
| Statin | 536 (37.3) | 298 (41.6) | 238 (33.0) | 0.001 |
| Comorbidity | ||||
| Cancer | 140 (9.7%) | 49 (6.8%) | 91 (12.6%) | <0.001 |
| Cerebrovascular disease | 202 (14.0%) | 112 (15.6%) | 90 (12.5%) | 0.09 |
| Chronic lung disease | 216 (15.0%) | 102 (14.2%) | 114 (15.8%) | 0.42 |
| Congestive heart failure | 147 (10.2%) | 82 (11.4%) | 65 (9%) | 0.14 |
| Coronary artery disease | 361 (25.1%) | 174 (24.3%) | 187 (25.9%) | 0.50 |
| Dementia | 34 (2.4%) | 11 (1.5%) | 23 (3.2%) | 0.05 |
| DM | 672 (46.7%) | 389 (54.3%) | 283 (39.2%) | <0.001 |
| Hypertension | 1004 (69.8%) | 530 (73.9%) | 474 (65.7%) | 0.001 |
| Liver cirrhosis | 24 (1.7%) | 5 (0.7%) | 19 (2.6%) | <0.01 |
| Peripheral arterial disease | 19 (1.3%) | 8 (1.1%) | 11 (1.5%) | 0.65 |
| Autoimmune disease | 75 (5.2%) | 36 (5.0%) | 39 (5.4%) | 0.81 |
| Laboratory data | ||||
| WBC count ×103/L | 7.1 (5.7–8.8) | 7.4 (6.0–9.1) | 6.8 (5.6–8.4) | <0.001 |
| Hemoglobin, g/dl | 10.4 (9–12) | 10.1 (8.8–11.7) | 10.6 (9.2–12.3) | 0.001 |
| Platelet count ×103/L | 218 (177–267) | 230 (190–279) | 203 (166–254) | <0.001 |
| Albumin, g/dl | 3.8 (3.4–4.2) | 3.7 (3.3–4.2) | 3.9 (3.6–4.3) | <0.001 |
| MCV, fl | 90.8 (87.2–95.6) | 87.17 (84.16–89.1) | 95.6 (93.83–98) | <0.001 |
| RDW, % | 14.3 (13.5–15.4) | 14.5 (13.6–15.6) | 14.2 (13.5–15.1) | <0.001 |
| BUN, mg/dl | 42.1 (29–63.3) | 44.2 (30–65.9) | 39.6 (28.3–60.8) | 0.001 |
| Creatinine, mg/dl | 2.9 (2.0–5.0) | 3.0 (2.0–5.2) | 2.7 (2.0–4.7) | 0.04 |
| eGFR, ml/min per 1.73 m2 | 19.7 (10.6–30.9) | 18.4 (10.1–30.3) | 20.6 (11.0–31.9) | 0.03 |
| Ca, mg/dl | 8.8 (8.4–9.2) | 8.8 (8.3–9.1) | 8.9 (8.4–9.2) | <0.01 |
| Phosphate, mg/dl | 4 (3.4–4.7) | 4.2 (3.5–5) | 3.9 (3.3–4.5) | <0.001 |
| Cholesterol, mg/dl | 180 (153–210) | 184 (155–217) | 177 (151–204) | <0.01 |
| Triglyceride, mg/dl | 130 (92–184) | 141 (103–203) | 119 (85–171) | <0.001 |
| GPT, U/L | 19 (13–31) | 18 (13–30) | 19 (13–31) | 0.28 |
| Uric acid, mg/dl | 7.9 (6.7–9) | 8.1 (6.9–9.3) | 7.7 (6.5–8.8) | <0.001 |
| 24-h Proteinuria, mg | 684.4 (169.5–2143.7) | 884.6 (215.4–2855.1) | 556.8 (117.1–1679.8) | <0.001 |
Values are expressed as means±SD, medians (interquartile range), or numbers (percentage). MCV, mean corpuscular volume; BMI, body mass index, ACE, angiotensin-converting enzyme; ARB, angiotensin II receptor blocker; DM, diabetes mellitus; WBC, white blood cell; RDW, red cell distribution width; Ca, calcium; GPT, glutamic-pyruvic transaminase.