Table 2.
Baseline demographics and lab characteristics by CKD status
| Variables | CKD 1–2 | CKD 3 | CKD 4–5 | P-value |
|---|---|---|---|---|
| n | 57 | 81 | 46 | |
| Age, years | 48.2 ± 11.9 | 58.9 ± 11.2 | 60.1 ± 11.6 | <0.001 |
| Female, % | 41 (71.9) | 54 (66.7) | 30 (65.2) | 0.729 |
| Race, % | ||||
| Black | 13 (22.8) | 23 (28.4) | 11 (23.9) | 0.878 |
| White | 38 (66.7) | 52 (64.2) | 32 (69.6) | |
| Others | 6 (10.5) | 6 (7.4) | 3 (6.5) | |
| Diabetes, % | 12 (21.1) | 33 (40.7) | 21 (45.7) | 0.017 |
| Weight, kg | 90.0 ± 24.4 | 92.9 ± 24.8 | 90.0 ± 27.6 | 0.749 |
| BMI, kg/m2 | 32.1 ± 8.0 | 33.2 ± 8.1 | 31.8 ± 8.6 | 0.587 |
| Systolic BP, mmHg | 132 ± 19 | 139 ± 23 | 136 ± 20 | 0.139 |
| Diastolic, mmHg | 77 ± 15 | 74 ± 10 | 72 ± 13 | 0.153 |
| Total cholesterol, mg/dL | 189 ± 48 | 179 ± 55 | 166 ± 46 | 0.068 |
| HDL, mg/dL | 47 ± 12 | 46 ± 15 | 44 ± 15 | 0.511 |
| Triglycerides, mg/dL | 214 ± 163 | 186 ± 113 | 159 ± 78 | 0.081 |
| Current smokers, % | 7 (12.3) | 12 (14.8) | 9 (19.6) | 0.587 |
| Serum albumin, g/dL | 3.79 ± 0.7 | 3.93 ± 0.6 | 3.92 ± 0.5 | 0.345 |
| C-reactive protein, mg/dLa | 0.40 (0.2–1.1) | 0.44 (0.2–0.96) | 0.29 (0.1–0.7) | 0.244 |
| Serum creatinine, mg/dL | 0.88 ± 0.20 | 1.52 ± 0.29 | 2.69 ± 0.69 | <0.001 |
| eGFR, mL/min | 89 ± 18 | 44 ± 8 | 23 ± 5 | <0.001 |
| UPC, g/g creatininea | 1.05 (0.15–2.87) | 0.40 (0.10–1.69) | 0.87 (0.28–2.92) | 0.155 |
| Medications, % | ||||
| Statin | 19 (33.3) | 50 (61.7) | 28 (60.9) | 0.002 |
| Diuretic | 25 (43.9) | 48 (59.3) | 26 (56.5) | 0.185 |
| Calcium channel blocker | 7 (12.3) | 38 (46.9) | 19 (41.3) | <0.001 |
| β-blockers | 9 (15.8) | 49 (60.5) | 29 (63.0) | <0.001 |
| ACEI/ARB/RB | 39 (68.4) | 55 (67.9) | 26 (56.5) | 0.359 |
| Other BP medication | 9 (15.8) | 26 (32.1) | 11 (23.9) | 0.091 |
| CVD group | ||||
| Never | 15 (26.3) | 21 (25.9) | 10 (21.7) | 0.037 |
| New | 16 (28.1) | 12 (14.8) | 18 (39.1) | |
| Old | 14 (45.6) | 21 (59.3) | 11 (39.1) | |
| Tryptophan metabolites | ||||
| Kynurenic acid, nMa | 0.27 (0.03–0.44) | 0.88 (0.49–1.60) | 1.92 (1.36–3.05) | 1E-17 |
| Kynurenine to tryptophan ratio | 0.06 ± 0.03 | 0.08 ± 0.03 | 0.09 ± 0.04 | 5E-08 |
| Hydroxykynurenine, nM | 86.0 ± 31.0 | 98.9 ± 35.9 | 124.2 ± 36.0b | 4E-07 |
| Kynurenine, μM | 3.9 ± 2.1 | 5.1 ± 2.1b | 5.6 ± 2.3 b | 1E-05 |
| Anthranilic acid, μM | 0.27 ± 0.02 | 0.27 ± 0.02 | 0.29 ± 0.02b | 0.001 |
| 3-hydroxyanthranilic acid, nM | 57.2 ± 45.6 | 70.5 ± 70.7 | 87.5 ± 84.3 | 0.081 |
| Quinolic acid, μMa | 0.21 (0.21–0.25) | 0.23 (0.21–0.26) | 0.23 (0.21–0.26) | 0.055 |
| Tryptophan, μM | 69.5 ± 27.3 | 71.4 ± 27.6 | 65.2 ± 24.5 | 0.455 |
Values are a mean and SD or counts and relative frequency.
a
UPC, C-reactive protein, kynurenic acid and quinolinic acid are presented as median and interquartile range.
b
Compared with other CVD groups.
BMI, body mass index; BP, blood pressure; HDL, high-density lipoprotein; UPC, urine protein creatinine ratio; ACEI, angiotensin-converting enzyme inhibitor; ARB, angiotensin receptor blocker; RB, renin blocker.