Table 1.
Baseline clinical data and outcomesa
| Characteristics | Non-AKI (n = 937) | AKI (n = 402) | P value |
|---|---|---|---|
| Demographic variables | |||
| Age, years | 52.0 (40.2–62.3) | 61.0 (47.0–71.0) | < 0.001 |
| Male sex, n (%) | 475 (50.7) | 233 (58.0) | 0.017 |
| BMI, kg/m2 | 22.19 (20.70–23.44) | 22.16 (20.57–23.11) | 0.477 |
| Preexisting clinical conditions | |||
| Hypertension, n (%) | 113 (12.1) | 123 (30.6) | < 0.001 |
| DM, n (%) | 41 (4.4) | 62 (15.4) | < 0.001 |
| CKD, n (%) | 16 (1.7) | 51 (12.7) | < 0.001 |
| CAD, n (%) | 17 (1.8) | 27 (6.7) | < 0.001 |
| Stroke, n (%) | 93 (9.9) | 93 (23.1) | < 0.001 |
| CHF, n (%) | 10 (1.1) | 25 (6.2) | < 0.001 |
| Malignancy, n (%) | 113 (12.1) | 64 (15.9) | 0.064 |
| COPD, n (%) | 15 (1.6) | 13 (3.2) | 0.062 |
| Chronic Liver disease, n (%) | 4 (0.4) | 8 (2.0) | 0.009 |
| Sepsis, n (%) | 76 (8.1) | 133 (33.1) | < 0.001 |
| Admission type, n (%) | < 0.001 | ||
| Elective surgical, n (%) | 821 (87.6) | 236 (58.7) | |
| Emergency surgical, n (%) | 51 (5.4) | 69 (17.2) | |
| Medical, n (%) | 65 (6.9) | 97 (24.1) | |
| Baseline serum creatinine, mg/dl | 0.69 (0.58–0.82) | 0.70 (0.57–0.94) | 0.053 |
| Baseline eGFR, ml/minute/1.73 m2 | 104.58 (93.69–115.48) | 98.53 (79.57–112.31) | < 0.001 |
| Serum creatinine at admission, mg/dl | 0.76 (0.64–0.92) | 1.02 (0.77–1.39) | < 0.001 |
| Cys C at admission, mg/L | 0.74 (0.59–0.91) | 1.04 (0.77–1.51) | < 0.001 |
| BUN at admission,mg/dl | 11.09 (8.88–13.73) | 15.13 (10.50–26.05) | < 0.001 |
| Albumin at admission, g/L | 31.70 (28.00–35.00) | 30.50 (25.85–34.74) | < 0.001 |
| Thyroid function at admission | |||
| FT3 (pmol/L) | 3.88 (3.39–4.32) | 3.52 (2.86–4.04) | < 0.001 |
| TT3 (nmol/L) | 0.99 (0.81–1.18) | 0.81 (0.58–1.05) | 0.001 |
| FT4 (pmol/L) | 13.37 (11.38–15.43) | 13.16 (10.86–15.66) | 0.436 |
| TT4 (nmol/L) | 99.80 (84.30–114.53) | 93.80 (71.58–110.82) | < 0.001 |
| TSH (μIU/L) | 1.36 (0.72–2.37) | 0.92 (0.52–1.86) | < 0.001 |
| Low T3 syndrome at admission, n (%) | 404 (43.1) | 246 (61.2) | < 0.001 |
| APACHE II score | 9 (7–13) | 15 (10–24) | < 0.001 |
| UP, ml/kg/h | 2.12 (1.61–2.80) | 2.00 (1.39–2.78) | 0.008 |
| Outcomes | |||
| Length of ICU stay, days | 2 (2–4) | 4 (2–9) | < 0.001 |
| Length of hospital stay, days | 15 (12–21) | 18 (13–28) | < 0.001 |
| RRT during ICU stay, n (%) | 3 (0.3) | 17 (4.2) | < 0.001 |
| ICU mortality, n (%) | 7 (0.7) | 34 (8.5) | < 0.001 |
| In-hospital mortality, n (%) | 8 (0.9) | 39 (9.7) | < 0.001 |
aThe non-normally distributed continuous variables are expressed as median (25th percentile to 75th percentile [interquartile range]). Categorical variables are expressed as n (%). APACHE II Acute Physiology and Chronic Health Evaluation score, AKI acute kidney injury, BMI body mass index, BUN blood urea nitrogen, CKD chronic kidney disease, defined as baseline estimated glomerular filtration rate < 60 ml/min/1.73 m2, Cys C cystatin C, DM diabetes mellitus, eGFR estimated glomerular filtration rate, FT3 free triiodothyronine, FT4 free thyroxine, ICU intensive care unit, RRT renal replacement therapy, TSH thyroid-stimulating-hormone, TT3 total triiodothyronine, TT4 total thyroxine, UP urine production first 24 h after admission. P value for global comparisons among groups by t or Kruskal-Wallis test, and chi-square test for continuous and categorical variables, respectively