Table 1.
Baseline demographic, clinical, and biochemical characteristics of 252 HD patients.
| All patients | Low TMAO group (≤4.73 μg/ml) | High TMAO group (>4.73 μg/ml) | p Value | |
|---|---|---|---|---|
| n = 252 | n = 126 | n = 126 | ||
| Demographics | ||||
| Age (years) | 57.1 ± 14.5 | 55.1 ± 15.6 | 59.1 ± 13.1 | 0.03 |
| Male sex | 141 (56.0) | 75 (59.5) | 66 (52.4) | 0.25 |
| BMI (kg/m2) | 22.2 ± 3.4 | 21.9 ± 3.6 | 22.5 ± 3.1 | 0.14 |
| Dialysis characteristics | ||||
| Duration (months) | 43.0 (19.3–74.5) | 37.5 (15.0–76.5) | 46.0 (26.8–70.5) | 0.17 |
| Interdialytic weight gain (%) | 3.2 ± 1.2 | 3.2 ± 1.1 | 3.2 ± 1.0 | 0.76 |
| Ultrafiltration volume (mL) | 2001 ± 748 | 1994 ± 782 | 2032 ± 704 | 0.68 |
| Systolic blood pressure (mmHg) | 136.7 ± 17.7 | 135.1 ± 17.0 | 138.3 ± 18.4 | 0.15 |
| Diastolic blood pressure (mmHg) | 82.3 ± 10.5 | 82.3 ± 10.4 | 82.3 ± 10.6 | 0.97 |
| Single-pool Kt/V | 1.40 ± 0.22 | 1.40 ± 0.21 | 1.41 ± 0.02 | 0.93 |
| Urinary volume (mL/kg per 24 h) | 0 (0–5.2) | 0.3 (0–7.4) | 0.2 (0.5.2) | 0.48 |
| eGFR (mL/min/1.73 m2) | 0 (0–0.5) | 0 (0–0.6) | 0 (0–0.4) | 0.34 |
| Normalized protein nitrogen appearance (g/kg per day) | 2.2 ± 0.6 | 2.1 ± 0.4 | 2.2 ± 0.5 | 0.16 |
| Smoking history (n, %) | 93 (36.9%) | 47 (37.3%) | 46 (36.5%) | 0.90 |
| Underlying kidney disease | 0.04 | |||
| Glomerular disease (n, %) | 112 (44.4%) | 56 (44.4%) | 56 (44.4%) | |
| Diabetic nephropathy (n, %) | 21 (8.3%) | 5 (4.0%) | 16 (12.7) | |
| Hypertensive nephropathy (n, %) | 20 (7.9%) | 12 (9.5%) | 8 (6.3%) | |
| Polycystic kidney disease (n, %) | 18 (7.1%) | 12 (9.5%) | 6 (4.8) | |
| Others (n, %) | 38 (15.1%) | 23 (18.3%) | 15 (11.9%) | |
| Unknown (n, %) | 43 (17.1%) | 18 (14.3%) | 25 (19.8%) | |
| Comorbidity | ||||
| Primary hypertension (n, %) | 79 (31.3%) | 40 (31.7%) | 39 (31.0%) | 0.89 |
| Coronary heart disease (n, %) | 17 (6.7%) | 9 (7.1%) | 8 (6.3%) | 0.80 |
| Diabetes (n, %) | 31 (12.3%) | 9 (7.1%) | 22 (17.5%) | 0.01 |
| Cerebral infarction (n, %) | 36 (14.3%) | 14 (11.1%) | 22 (17.5%) | 0.15 |
| Cerebral hemorrhage (n, %) | 8 (3.2%) | 5 (4.0%) | 3 (2.4%) | 0.47 |
| Gout (n, %) | 55 (21.8%) | 30 (23.8%) | 25 (19.8%) | 0.45 |
| Medications (%) | ||||
| CCB (n, %) | 156 (61.9%) | 75 (59.5%) | 81 (64.3%) | 0.44 |
| ACEI (n, %) | 42 (16.7%) | 19 (15.1%) | 23 (18.3%) | 0.50 |
| ARB (n, %) | 67 (26.6%) | 36 (28.6%) | 31 (24.6%) | 0.48 |
| β-Blocker (n, %) | 40 (15.9%) | 22 (17.5%) | 18 (14.3%) | 0.49 |
| α-Blocker (n, %) | 46 (18.3%) | 21 (16.7%) | 25 (19.8) | 0.51 |
| Aspirin (n, %) | 51 (20.2%) | 22 (17.5%) | 29 (23.0%) | 0.27 |
| Statin (n, %) | 14 (5.6%) | 6 (4.8%) | 8 (6.3%) | 0.58 |
| Calcium supplement (n, %) | 166 (65.9%) | 83 (65.9%) | 83 (65.9%) | 1.0 |
| Calcitriol (n, %) | 137 (54.4%) | 77 (61.1%) | 60 (47.6%) | 0.03 |
| Predialysis laboratory tests | ||||
| Albumin (g/L) | 39.2 ± 3.7 | 39.1 ± 3.8 | 39.3 ± 3.6 | 0.55 |
| Prealbumin (g/L) | 0.33 ± 0.09 | 0.33 ± 0.08 | 0.33 ± 0.09 | 0.53 |
| Hemoglobin (g/L) | 103.1 ± 16.0 | 103.9 ± 17.6 | 102.3 ± 14.3 | 0.42 |
| BUN (mmol/L) | 23.9 ± 5.4 | 23.5 ± 5.1 | 24.3 ± 5.7 | 0.25 |
| Serum creatinine (μmol/L) | 1020.7 ± 261.2 | 1012.7 ± 261.2 | 1028.8 ± 262.0 | 0.63 |
| Uric acid (μmol/L) | 434.9 ± 85.3 | 431.6 ± 78.2 | 438.2 ± 92.0 | 0.54 |
| Calcium (mmol/L) | 2.22 ± 0.21 | 2.22 ± 0.18 | 2.21 ± 0.23 | 0.58 |
| Phosphorus (mmol/L) | 2.17 ± 0.63 | 2.16 ± 0.66 | 2.18 ± 0.61 | 0.86 |
| Alkaline phosphatase (U/L) | 72.0 (56.0–92.5) | 72.0 (55.0–100.0) | 73.0 (56.0–87.5) | 0.78 |
| 25-Hydroxy vitamin D (nmol/L) | 57.5 ± 19.0 | 56.3 ± 18.9 | 58.8 ± 19.0 | 0.31 |
| iPTH (pg/mL) | 272.9 (137.0–553.6) | 271.5 (139.5–552.8) | 278.5 (136.7–565.9) | 0.84 |
| UIBC (μmol/L) | 25 (20–29) | 24 (21–28) | 26 (20–30) | 0.40 |
| TIBC (μmol/L) | 36 (32–41) | 36 (31–41) | 36 (33–40) | 0.52 |
| Iron (μmol/L) | 10.5 (7.1–14.2) | 10.6 (7.7–14.9) | 10.0 (7.0–13.8) | 0.60 |
| Transferrin (g/L) | 1.9 (1.6–2.1) | 1.8 (1.6–2.1) | 1.9 (1.7–2.2) | 0.23 |
| Ferritin (ng/mL) | 126.8 (68.5–265.2) | 124.6 (70.1–262.1) | 128.6 (61.6–282.3) | 0.72 |
| hsCRP (mg/L) | 2.1 (0.7–6.3) | 2.1 (0.7–6.2) | 2.2 (0.8–7.0) | 0.37 |
| Triglycerides (mmol/L) | 1.4 (1.1–1.9) | 1.4 (1.1–1.9) | 1.4 (1.1–1.9) | 0.55 |
| Total cholesterol (mmol/L) | 4.4 ± 1.1 | 4.3 ± 1.1 | 4.4 ± 1.2 | 0.31 |
| HDL-C (mmol/L) | 1.1 ± 0.3 | 1.2 ± 0.3 | 1.1 ± 0.3 | 0.37 |
| LDL-C (mmol/L) | 2.5 ± 0.9 | 2.4 ± 0.8 | 2.5 ± 0.9 | 0.38 |
| Apo-A (g/L) | 1.2 ± 0.3 | 1.2 ± 0.3 | 1.2 ± 0.3 | 0.84 |
| Apo-B (g/L) | 0.8 ± 0.2 | 0.8 ± 0.2 | 0.8 ± 0.2 | 0.40 |
| Lp (a) (mg/L) | 173 (115–281) | 178 (115–309) | 169 (115–251) | 0.21 |
| Homocysteine (μmol/L) | 34.7 (27.8–43.1) | 34.6 (27.9–43.1) | 35.1 (27.7–43.1) | 0.98 |
| β2-Microglobulin (mg/L) | 35.8 ± 11.4 | 34.0 ± 11.6 | 37.7 ± 11.0 | 0.008 |
| TMAO (μg//ml) | 4.73 (3.20–6.69) | 3.30 (2.25–4.00) | 6.67 (5.54–8.65) | <0.001 |
Data are presented as means ± SDs or medians (interquartile ranges) for continuous variables and as n (%) for categorical variables.
Abbreviations here and below: ACEI: angiotensin-converting-enzyme inhibitor; Apo: apolipoprotein; ARB: angiotensin II receptor blocker; BMI: body mass index; BUN: blood urea nitrogen; CCB: calcium channel blocker; eGFR: estimated glomerular filtration rate; HDL-C: high-density lipoprotein cholesterol; hsCRP: high-sensitivity C-reactive protein; iPTH: intact parathyroid hormone; LDL-C: low-density lipoprotein cholesterol; Lp: lipoprotein; TIBC: total-iron binding capacity; UIBC: unsaturated iron-binding capacity.
The bold values represents as Age, underlying kidney disease, Comorbid of diabetes, calcitriol (active vitamin D), β2-Microglobulin, are related to the patients' outcomes, and we developed eight different multivariate models to adjust for these confounders. TMAO is the factor we aimed to examine whether it is associated with cardiovascular death and all-cause death.