Table 1. Baseline characteristics according to the status of A-SAG threshold.
| A-SAG < 9.48 mmol/L (n = 183) | A-SAG ≥ 9.48 mmol/L (n = 257) | P | |
|---|---|---|---|
| Age (years) | 56.0 ± 13.1 | 57.3 ± 13.2 | 0.297 |
| Male sex | 132/183 (72.1) | 162/257 (63.0) | 0.046 |
| Diabetic nephropathy | 83/183 (45.4) | 121/257 (47.1) | 0.720 |
| Systolic BP (mmHg)b | 131.0 ± 15.0 | 130.9 ± 14.1 | 0.931 |
| eGFR (mL/min/1.73m2) | 24.2 ± 6.8 | 22.5 ± 6.7 | 0.012 |
| Blood urea nitrogen (mmol/L) | 14.3 ± 4.1 | 15.9 ± 5.6 | <0.001 |
| Creatinine (μmol/L)a | 229.8 (203.3–282.9) | 238.7 (203.3–291.7) | 0.157 |
| Urine protein creatinine ratio (g/g)a,b | 1.1 (0.4–2.9) | 1.3 (0.5–2.9) | 0.315 |
| Total calcium (mmol/L)b | 2.2 ± 0.1 | 2.2 ± 0.2 | 0.466 |
| Inorganic phosphorus (mmol/L) | 1.2 ± 0.2 | 1.3 ± 0.3 | 0.087 |
| Serum glucose (mmol/L)b | 6.3 ± 2.2 | 6.6 ± 2.8 | 0.287 |
| Serum albumin (g/L)a | 41.0 (39.0–44.0) | 40.0 (38.0–43.0) | 0.081 |
| C-reactive protein (nmol/L)a,b | 10.5 (1.9–37.9) | 12.4 (1.0–58.6) | 0.351 |
| Sodium (mmol/L) | 140.6 ± 2.2 | 140.5 ± 2.4 | 0.705 |
| Potassium (mmol/L) | 5.1 ± 0.6 | 5.0 ± 0.6 | 0.045 |
| Chloride (mmol/L) | 108.7 ± 3.4 | 107.5 ± 3.8 | 0.001 |
| Total CO2 (mmol/L) | 24.0 ± 2.9 | 21.6 ± 3.3 | < 0.001 |
| SAG (mmol/L) | 7.9 ± 1.7 | 11.5 ± 2.1 | < 0.001 |
| A-SAG (mmol/L) | 7.8 ± 1.4 | 11.5 ± 1.9 | < 0.001 |
| Log serum total IS (mg/L)b | 1.4 ± 1.1 | 1.4 ± 1.3 | 0.970 |
| Serum B2MG (mg/L)b | 6.5 ± 2.5 | 6.9 ± 2.7 | 0.102 |
Values were expressed as mean ± standard deviation for continuous variables and n/total (%) for categorical variables. Differences were evaluated by t-test or Mann-Whitney U test for continuous variables, and chi-square test for categorical variables. BP, blood pressure; eGFR, estimated glomerular filtration rate; SAG, serum anion gap; A-SAG, albumin-adjusted serum anion gap; IS, indoxyl sulfate; B2MG, beta-2 microglobulin.
a denotes variables with non-normal distribution. Values were expressed as median (interquartile range) and differences were evaluated by Mann-Whitney U test in these variables.
b denotes incomplete data. The missing rates of the variables were less than 6.1%.