Table 1. Baseline characteristics of patients with stages 3–4 CKD, stratified by Hb and HbA1c quartiles.
| All | Hemoglobin < 10 g/dl | P | Hemoglobin ≥ 10 g/dl | P | |||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| HbA1c quartiles | HbA1c quartiles | ||||||||||
| Q1 | Q2 | Q3 | Q4 | Q1 | Q2 | Q3 | Q4 | ||||
| HbA1c (%) | < 6.4 | 6.4–7.2 | 7.2–8.3 | ≥ 8.3 | < 6.4 | 6.4–7.2 | 7.2–8.3 | ≥ 8.3 | |||
| No. of patients | 1558 | 136 | 90 | 91 | 94 | 256 | 282 | 322 | 287 | ||
| Demographics and medical history | |||||||||||
| Age (years) | 64.7 (12.8) | 67.2 (12.9) | 66.0 (12.4) | 65.1 (11.6) | 62.8 (13.3) | 0.001 | 67.0 (11.9) | 63.6 (14.2) | 64.3 (13.3) | 62.9 (11.6) | 0.001 |
| Female (n[%]) | 589 (37.8%) | 81 (59.6%) | 38 (42.2%) | 50 (54.9%) | 53 (56.4%) | 0.073 | 82 (32.0%) | 89 (31.6%) | 107 (33.2%) | 89 (31.0%) | 0.944 |
| Hypertension (n[%]) | 1695 (71%) | 107 (78.7%) | 63 (70.0%) | 61 (67.0%) | 62 (66.0%) | 0.121 | 186 (72.7%) | 171 (60.6%) | 198 (61.5%) | 177 (61.7%) | 0.011 |
| CVD (n[%]) | 812 (33.8%) | 52 (38.2%) | 36 (40.0%) | 28 (30.8%) | 28 (29.8%) | 0.327 | 88 (34.4%) | 86 (30.5%) | 69 (21.4%) | 99 (34.5%) | 0.001 |
| CHF (n[%]) | 406 (16.9%) | 28 (20.6%) | 22 (24.4%) | 21 (23.1%) | 16 (17.0%) | 0.620 | 28 (10.9%) | 42 (14.9%) | 22 (6.8%) | 41 (14.3%) | 0.007 |
| Stroke (n[%]) | 492 (20.5%) | 35 (25.7%) | 21 (23.3%) | 16 (17.6%) | 13 (13.8%) | 0.125 | 68 (26.6%) | 52 (18.4%) | 48 (14.9%) | 66 (23.0%) | 0.003 |
| BMI (m2/kg) | 25.2 (3.9) | 23.4 (3.4) | 24.4 (4.8) | 24.2 (3.8) | 24.6 (3.9) | 0.037 | 25.1 (3.6) | 26.1 (4.0) | 26.0 (4.1) | 25.9 (3.7) | 0.102 |
| MAP (mmHg) | 99.3 (14.0) | 96.7 (14.1) | 96.9 (15.1) | 99.2 (14.1) | 98.8 (13.8) | 0.034 | 99.2 (13.6) | 98.7 (13.1) | 100.2 (14.0) | 101.1 (14.8) | 0.003 |
| Hb and iron profiles | |||||||||||
| Hemoglobin (g/dl) | 11.6 (2.2) | 8.9 (0.9) | 8.9 (1.1) | 8.9 (0.9) | 9.1 (0.8) | 0.012 | 12.6 (1.6) | 12.7 (1.7) | 12.5 (1.7) | 12.4 (1.6) | 0.644 |
| Iron (mg/dl) | 69.8 (27.2) | 57.6 (26.3) | 59.0 (30.0) | 54.1 (25.6) | 60.8 (30.1) | 0.617 | 83.7 (28.3) | 77.0 (26.9) | 71.5 (28.5) | 70.7 (29.6) | <0.001 |
| Ferritin (ng/ml) | 212 (110–387) |
201 (109–454) |
273 (113–481) |
240 (104–467) |
222 (114–413) |
0.761 | 201 (108–345) |
203 (96–352) |
193 (88–331) |
200 (107–387) |
0.311 |
| Iron deficiency (n[%]) a | 547 (46.2%) | 69 (67.6%) | 49 (69.0%) | 33 (62.3%) | 36 (58.1%) | 0.577 | 66 (29.9%) | 80 (35.7%) | 109 (48.7%) | 105 (46.5%) | <0.001 |
| Laboratory data | |||||||||||
| eGFR (ml/min/1.73 m2) | 33.0 (11.9) | 25.3 (8.6) | 26.6 (9.5) | 27.6 (10.7) | 28.2 (12.3) | 0.897 | 34.5 (11.5) | 36.8 (11.8) | 35.8 (11.8) | 34.0 (11.5) | 0.086 |
| UPCR (mg/g) | 1164 (322–3297) | 1714 (711–4227) |
1957 (652–5390) |
2970 (977–6135) |
3106 (1345–5787) |
0.073 | 567 (250–1757) |
545 (167–1532) |
923 (268–2885) |
1499 (452–4187) | <0.001 |
| Albumin (g/dl) | 3.8 (0.6) | 3.5 (0.7) | 3.5 (0.6) | 3.4 (0.7) | 3.4 (0.6) | 0.430 | 4.0 (0.5) | 4.0 (0.5) | 3.9 (0.6) | 3.7 (0.5) | 0.242 |
| Blood glucose (mg/dl) | 134.8 (56.4) | 105.4 (31.4) | 127.6 (46.0) | 141.2 (59.0) | 162.5 (75.6) | <0.001 | 106.4 (28.3) | 118.2 (41.2) | 139.3 (45.7) | 176.2 (71.5) | <0.001 |
| HbA1c (%) | 7.6 (1.8) | 5.7 (0.5) | 6.8 (0.2) | 7.7 (0.3) | 9.7 (1.5) | <0.001 | 5.8 (0.5) | 6.8 (0.2) | 7.7 (0.3) | 10.2 (1.5) | <0.001 |
| Total calcium (mg/dl) | 9.3 (0.7) | 9.0 (0.7) | 8.9 (0.7) | 9.1 (0.6) | 9.2 (0.8) | 0.001 | 9.3 (0.6) | 9.4 (0.6) | 9.3 (0.7) | 9.3 (0.7) | 0.003 |
| Phosphate (mg/dl) | 4.0 (0.9) | 4.4 (0.7) | 4.4 (1.0) | 4.2 (0.9) | 4.2 (0.9) | 0.155 | 3.8 (0.8) | 3.8 (0.8) | 3.9 (0.9) | 4.0 (0.9) | 0.001 |
| Uric acid (mg/dl) | 7.8 (1.9) | 7.8 (1.7) | 8.1 (2.1) | 7.5 (2.0) | 8.2 (2.9) | <0.001 | 7.9 (1.9) | 7.9 (1.8) | 7.6 (1.7) | 7.6 (1.9) | 0.003 |
| Total cholesterol (mg/dl) | 193 (164–226) | 177 (146–210) | 177 (153–216) | 187 (162–230) | 201 (167–246) | <0.001 | 187 (164–215) | 194 (164–223) | 196 (164–225) | 209 (174–250) | <0.001 |
| Triglyceride (mg/dl) | 140 (100–208) | 115 (78–166) | 119 (86–158) | 150 (96–202) | 157 (108–241) | <0.001 | 124 (92–182) | 138 (98–210) | 145 (103–212) | 180 (118–261) | <0.001 |
| CRP (mg/l) | 1.6 (0.4–10.0) | 1.6 (0.5–10.4) | 4.4 (0.7–19.7) | 3.0 (0.5–35.0) | 1.3 (0.4–13.3) | 0.184 | 1.0 (0.3–5.7) | 1.2 (0.4–7.9) | 1.5 (0.5–8.7) | 2.1 (0.5–14.6) | 0.017 |
Data expressed as the mean ± standard deviation, median (interquartile range), or count (percentage).
Abbreviations: HbA1c, glycated hemoglobin; CVD, cardiovascular disease; CHF, congestive heart failure; BMI, body mass index; MAP, mean arterial pressure; Hb, hemoglobin; eGFR, estimated glomerular filtration rate; UPCR, urine protein-to-creatinine ratio; CRP, C-reactive protein.
a. Iron deficiency was defined as iron saturation <20% or ferritin < 100 ng/ml.