Table 1.
Baseline characteristics of inpatients [mean ± SD; n (%)]
| Features | Total (n = 1633) | NKD (n = 1138) | Acute/subacute renal impairment (n = 495) | |||
|---|---|---|---|---|---|---|
| AKI recovery (n = 173) | Subacute AKD (n = 257) | AKD with AKI (n = 65) | P-value | |||
| Demographics | ||||||
| Age (years) | 68.37 ± 13.38 | 68.24 ± 13.46 | 67.06 ± 13.98 | 69.30 ± 11.99 | 70.45 ± 15.23 | 0.55 |
| Male (%) | 991 (60.69) | 691 (60.72) | 101 (58.38) | 165 (64.20) | 34 (52.31) | 1 |
| Smokers (%) | 559 (34.23) | 395 (34.71) | 57 (32.95) | 88 (34.24) | 19 (29.23) | 0.57 |
| Drinkers (%) | 442 (27.07) | 307 (26.98) | 47 (27.17) | 77 (29.96) | 11 (16.92) | 0.95 |
| Surgical history (%) | 579 (35.46) | 390 (34.27) | 60 (34.68) | 109 (42.41) | 20 (30.77) | 0.14 |
| Blood transfusion (%) | 167 (10.23) | 101 (8.88) | 30 (17.34) | 26 (10.12) | 10 (15.38) | 0.01 |
| BMI (kg/m2) | 23.99 ± 3.22 | 23.95 ± 3.15 | 24.20 ± 3.38 | 24.00 ± 3.42 | 24.13 ± 3.32 | 0.42 |
| SBP (mmHg) | 142.79 ± 23.71 | 142.33 ± 22.71 | 142.18 ± 25.69 | 144.73 ± 25.24 | 144.77 ± 28.79 | 0.24 |
| DBP (mmHg) | 81.34 ± 13.99 | 81.18 ± 13.55 | 81.29 ± 15.36 | 82.12 ± 14.21 | 81.14 ± 16.88 | 0.49 |
| Fever (%) | 137 (8.39) | 95 (8.35) | 13 (7.51) | 21 (8.17) | 8 (12.31) | 1 |
| Respiratory rate (bpm) | ||||||
| < 12 | 3 (0.18) | 1 (0.09) | 1 (0.58) | 1 (0.39) | 0 (0.00) | 0.13 |
| 12–20 | 1371 (83.96) | 970 (85.24) | 142 (82.08) | 211 (82.10) | 48 (73.85) | |
| > 20 | 259 (15.86) | 167 (14.67) | 30 (17.34) | 45 (17.51) | 17 (26.15) | |
| Heart rate (bpm) | ||||||
| < 60 | 135 (8.27) | 93 (8.17) | 20 (11.56) | 20 (7.78) | 2 (3.08) | 0.18 |
| 60–100 | 1376 (84.26) | 965 (84.80) | 140 (80.92) | 211 (82.10) | 60 (92.31) | |
| > 100 | 122 (7.47) | 80 (7.03) | 13 (7.51) | 26 (10.12) | 3 (4.62) | |
| Laboratory tests | ||||||
| RBC (× 1012/L) | 4.20 ± 0.76 | 4.24 ± 0.72 | 4.06 ± 0.93 | 4.21 ± 0.75 | 3.96 ± 0.81 | 0.01 |
| WBC (× 109/L) | 8.27 ± 4.30 | 7.96 ± 3.96 | 9.54 ± 4.11 | 8.14 ± 4.36 | 10.95 ± 7.54 | < 0.01 |
| Neutrophil count (× 109/L) | 5.89 ± 3.62 | 5.56 ± 3.20 | 7.44 ± 3.99 | 5.67 ± 3.92 | 8.53 ± 5.59 | < 0.01 |
| Hemoglobin (g/L) | 126.30 ± 23.92 | 127.12 ± 23.17 | 122.21 ± 27.72 | 126.99 ± 23.85 | 120.05 ± 24.85 | 0.04 |
| Platelet (× 109/L) | 217.02 ± 80.16 | 220.04 ± 79.67 | 207.49 ± 91.85 | 212.74 ± 69.98 | 206.52 ± 90.69 | 0.02 |
| MCV (fL) | 89.88 ± 6.19 | 89.65 ± 6.21 | 90.36 ± 6.68 | 90.12 ± 5.26 | 91.64 ± 7.59 | 0.02 |
| Hematocrit (%) | 37.66 ± 6.86 | 37.83 ± 6.58 | 36.55 ± 8.11 | 37.86 ± 7.01 | 36.91 ± 7.36 | 0.14 |
| MCHC (g/L) | 334.36 ± 14.96 | 334.83 ± 14.91 | 331.73 ± 17.11 | 334.46 ± 13.32 | 332.72 ± 15.22 | 0.05 |
| MCH (pg) | 30.06 ± 2.43 | 30.03 ± 2.49 | 29.97 ± 2.56 | 30.14 ± 2.06 | 30.45 ± 2.40 | 0.47 |
| PT (s) | 11.44 ± 3.07 | 11.29 ± 2.79 | 11.94 ± 3.21 | 11.63 ± 3.94 | 12.06 ± 3.31 | < 0.01 |
| PTA (%) | 110.89 ± 32.64 | 112.42 ± 32.75 | 103.35 ± 28.00 | 109.94 ± 32.15 | 107.84 ± 40.63 | < 0.01 |
| Fibrinogen (g/L) | 3.62 ± 1.10 | 3.62 ± 1.10 | 3.70 ± 1.15 | 3.53 ± 1.10 | 3.80 ± 1.01 | 1 |
| Scr (μmol/L) | 102.74 ± 99.40 | 96.87 ± 73.86 | 146.73 ± 205.03 | 102.36 ± 91.89 | 90.01 ± 47.58 | < 0.01 |
| Bassline eGFR (ml/min/1.73 m2) | 72.43 ± 25.28 | 72.92 ± 23.81 | 72.50 ± 34.59 | 70.12 ± 23.44 | 72.84 ± 28.08 | 0.24 |
| BUN (mmol/L) | 7.01 ± 4.87 | 6.94 ± 5.15 | 7.18 ± 3.65 | 7.35 ± 4.72 | 6.45 ± 2.70 | 0.38 |
| Uric acid (μmol/L) | 289.96 ± 121.17 | 285.10 ± 111.32 | 301.23 ± 161.68 | 299.71 ± 114.52 | 306.46 ± 173.41 | 0.01 |
| ALT (U/L) | 37.52 ± 173.35 | 29.84 ± 52.17 | 57.22 ± 171.09 | 54.22 ± 392.56 | 53.42 ± 139.13 | 0.01 |
| AST (U/L) | 35.22 ± 158.95 | 25.86 ± 29.57 | 60.74 ± 185.51 | 48.78 ± 343.63 | 77.48 ± 241.00 | < 0.01 |
| GGT (U/L) | 43.37 ± 83.36 | 41.18 ± 74.95 | 51.24 ± 87.30 | 48.08 ± 115.50 | 42.20 ± 56.68 | 0.11 |
| ADA (U/L) | 12.51 ± 7.18 | 12.42 ± 7.43 | 13.26 ± 7.16 | 12.60 ± 6.58 | 11.74 ± 4.37 | 0.44 |
| LDH (U/L) | 211.61 ± 160.31 | 197.80 ± 109.05 | 282.95 ± 273.07 | 203.42 ± 119.54 | 295.85 ± 402.37 | < 0.01 |
| ALP (U/L) | 80.32 ± 54.03 | 79.20 ± 47.59 | 83.40 ± 57.54 | 83.06 ± 77.08 | 80.84 ± 38.36 | 0.2 |
| Total bilirubin (μmol/L) | 17.76 ± 17.93 | 17.11 ± 15.02 | 21.92 ± 34.25 | 17.80 ± 14.22 | 17.94 ± 13.27 | 0.03 |
| Total protein (g/L) | 62.77 ± 7.65 | 62.81 ± 7.34 | 62.59 ± 8.66 | 63.18 ± 8.12 | 60.95 ± 8.11 | 0.76 |
| Albumin (g/L) | 34.71 ± 5.86 | 34.92 ± 5.67 | 33.71 ± 6.21 | 35.00 ± 6.31 | 32.61 ± 5.77 | 0.03 |
| HDLC (mmol/L) | 1.18 ± 0.36 | 1.18 ± 0.35 | 1.14 ± 0.49 | 1.20 ± 0.32 | 1.16 ± 0.36 | 0.86 |
| LDLC (mmol/L) | 2.55 ± 1.04 | 2.56 ± 1.02 | 2.46 ± 1.05 | 2.58 ± 1.07 | 2.44 ± 1.29 | 0.52 |
| Total cholesterol (mmol/L) | 4.48 ± 1.56 | 4.48 ± 1.44 | 4.47 ± 2.21 | 4.49 ± 1.42 | 4.44 ± 2.10 | 0.95 |
| Triglycerides (mmol/L) | 1.38 ± 1.15 | 1.36 ± 1.04 | 1.57 ± 1.85 | 1.35 ± 0.84 | 1.27 ± 1.55 | 0.36 |
| Lipoprotein a (mg/L) | 353.00 ± 380.48 | 326.11 ± 309.98 | 547.75 ± 717.17 | 336.54 ± 303.92 | 370.43 ± 340.58 | < 0.01 |
| Blood glucose (mmol/L) | 7.18 ± 3.52 | 6.90 ± 3.18 | 8.77 ± 4.78 | 7.11 ± 3.47 | 8.03 ± 4.12 | < 0.01 |
| Sodium (mmol/L) | 140.44 ± 5.02 | 140.52 ± 4.82 | 139.51 ± 6.40 | 140.85 ± 4.38 | 139.95 ± 6.40 | 0.36 |
| Calcium (mmol/L) | 2.14 ± 0.18 | 2.15 ± 0.18 | 2.16 ± 0.20 | 2.09 ± 0.18 | 2.12 ± 0.21 | 0.01 |
| Potassium (mmol/L) | 4.03 ± 0.55 | 4.05 ± 0.53 | 4.05 ± 0.58 | 4.02 ± 0.64 | 3.82 ± 0.59 | 0.14 |
| Magnesium (mmol/L) | 0.89 ± 0.12 | 0.91 ± 0.12 | 0.85 ± 0.10 | 0.89 ± 0.12 | 0.84 ± 0.10 | < 0.01 |
| Chloride (mmol/L) | 103.32 ± 5.64 | 103.60 ± 5.43 | 103.10 ± 6.23 | 102.65 ± 5.86 | 101.73 ± 6.30 | < 0.01 |
| Phosphorus (mmol/L) | 1.04 ± 0.30 | 1.05 ± 0.30 | 1.06 ± 0.26 | 0.97 ± 0.29 | 1.00 ± 0.24 | 0.01 |
| Anion gap (mmol/L) | 12.26 ± 3.26 | 12.41 ± 3.19 | 11.55 ± 3.21 | 12.23 ± 3.50 | 11.45 ± 3.40 | < 0.01 |
| Urinalysis | ||||||
| pH | 6.01 ± 0.60 | 5.98 ± 0.60 | 6.14 ± 0.64 | 5.99 ± 0.57 | 6.20 ± 0.66 | < 0.01 |
| Specific gravity | 1.02 ± 0.01 | 1.02 ± 0.01 | 1.01 ± 0.01 | 1.02 ± 0.01 | 1.01 ± 0.01 | < 0.01 |
| Protein | 501 (30.68) | 334 (29.35) | 65 (37.57) | 83 (32.30) | 19 (29.23) | 0.09 |
| Glucose | 935 (57.26) | 610 (53.60) | 93 (53.76) | 189 (73.54) | 43 (66.15) | < 0.01 |
| Hematuria | 1304 (79.85) | 854 (75.04) | 149 (86.13) | 242 (94.16) | 59 (90.77) | < 0.01 |
| Positive fecal occult blood, n (%) | 122 (7.47) | 77 (6.77) | 10 (5.78) | 33 (12.84) | 2 (3.08) | 0.12 |
| Comorbidities, n (%) | ||||||
| Cerebral hemorrhage | 110 (6.74) | 81 (7.12) | 9 (5.20) | 16 (6.23) | 4 (6.15) | 0.41 |
| Epilepsy | 31 (1.90) | 20 (1.76) | 3 (1.73) | 8 (3.11) | 0 (0.00) | 0.66 |
| Cerebral aneurysm | 37 (2.27) | 30 (2.64) | 4 (2.31) | 3 (1.17) | 0 (0.00) | 0.18 |
| Shock | 16 (0.98) | 10 (0.88) | 1 (0.58) | 4 (1.56) | 1 (1.54) | 0.72 |
| Diabetes mellitus | 565 (34.60) | 379 (33.30) | 65 (37.57) | 101 (39.30) | 20 (30.77) | 0.11 |
| Hypertension | 1103 (67.54) | 765 (67.22) | 115 (66.47) | 183 (71.21) | 40 (61.54) | 0.72 |
| CHD | 580 (35.52) | 391 (34.36) | 71 (41.04) | 95 (36.96) | 23 (35.38) | 0.15 |
| Heart failure | 271 (16.60) | 183 (16.08) | 23 (13.29) | 56 (21.79) | 9 (13.85) | 0.44 |
| Myocardial infarction | 92 (5.63) | 57 (5.01) | 12 (6.94) | 18 (7.00) | 5 (7.69) | 0.12 |
| Cardiac arrhythmia | 359 (21.98) | 236 (20.74) | 46 (26.59) | 58 (22.57) | 19 (29.23) | 0.08 |
| Urinary tract infection | 50 (3.06) | 29 (2.55) | 7 (4.05) | 11 (4.28) | 3 (4.62) | 0.09 |
| CKD | 115 (7.04) | 66 (5.80) | 27 (15.61) | 13 (5.06) | 9 (13.85) | < 0.01 |
| COPD | 44 (2.69) | 27 (2.37) | 8 (4.62) | 8 (3.11) | 1 (1.54) | 0.29 |
| Pulmonary infection | 415 (25.41) | 270 (23.73) | 34 (19.65) | 96 (37.35) | 15 (23.08) | 0.02 |
| Gastrointestinal bleeding | 31 (1.90) | 23 (2.02) | 0 (0.00) | 6 (2.33) | 2 (3.08) | 0.72 |
| Medications, n (%) | ||||||
| ACEI/ARB | 881 (53.95) | 598 (52.55) | 91 (52.60) | 147 (57.20) | 45 (69.23) | 0.1 |
| CCB | 776 (47.52) | 527 (46.31) | 86 (49.71) | 127 (49.42) | 36 (55.38) | 0.15 |
| β-Blocker | 559 (34.23) | 352 (30.93) | 84 (48.55) | 85 (33.07) | 38 (58.46) | < 0.01 |
| Diuretics | 1081 (66.20) | 714 (62.74) | 138 (79.77) | 171 (66.54) | 58 (89.23) | < 0.01 |
| Proton pump inhibitors | 1073 (65.71) | 716 (62.92) | 132 (76.30) | 169 (65.76) | 56 (86.15) | < 0.01 |
| Statins | 1119 (68.52) | 780 (68.54) | 119 (68.79) | 175 (68.09) | 45 (69.23) | 1 |
| Antibiotics | 987 (60.44) | 649 (57.03) | 132 (76.30) | 149 (57.98) | 57 (87.69) | < 0.01 |
| NSAIDs | 204 (12.49) | 148 (13.01) | 17 (9.83) | 34 (13.23) | 5 (7.69) | 0.38 |
| Metformin | 232 (14.21) | 171 (15.03) | 19 (10.98) | 36 (14.01) | 6 (9.23) | 0.17 |
| Antithrombotic drugs | 1442 (88.30) | 1013 (89.02) | 153 (88.44) | 222 (86.38) | 54 (83.08) | 0.2 |
| Adrenergic drugs | 291 (17.82) | 205 (18.01) | 26 (15.03) | 49 (19.07) | 11 (16.92) | 0.81 |
| Cardiac glycosides | 253 (15.49) | 150 (13.18) | 21 (12.14) | 59 (22.96) | 23 (35.38) | < 0.01 |
| Outcome | ||||||
| Mortality, n (%) | 79 (4.84) | 23 (2.02) | 20 (11.56) | 11 (4.28) | 25 (38.46) | < 0.01 |
| Renal function grade, n (%) | ||||||
| 0 | 1138 (69.69) | 1138 (100.00) | 0 (0.00) | 0 (0.00) | 0 (0.00) | < 0.01 |
| 1 | 359 (21.98) | 0 (0.00) | 140 (80.92) | 189 (73.54) | 30 (46.15) | |
| 2 | 82 (5.02) | 0 (0.00) | 20 (11.56) | 47 (18.29) | 15 (23.08) | |
| 3 | 54 (3.31) | 0 (0.00) | 13 (7.51) | 21 (8.17) | 20 (30.77) | |
| Length of stay (days) | 23.02 ± 12.51 | 23.52 ± 11.68 | 23.23 ± 19.29 | 21.25 ± 9.02 | 20.75 ± 14.70 | 0.01 |
SD: Standard deviation; NKD: No kidney disease; AKI: Acute kidney injury; AKD: Acute kidney disease; BMI: Body mass index; SBP: Systolic blood pressure; DBP: Diastolic blood pressure; RBC: Red blood cell; WBC: White blood cell; MCV: Mean corpuscular volume; MCHC: Mean corpuscular hemoglobin concentration; MCH: Mean corpuscular hemoglobin; PT: Prothrombin time; PTA: Prothrombin activity; Scr: Serum creatinine; eGFR: Estimated glomerular filtration rate; BUN: Blood urea nitrogen; ALT: Alanine transaminase; AST: Aspartate transaminase; GGT: Gamma-glutamyl transferase; ADA: Adenosine deaminase; LDH: Lactate dehydrogenase; ALP: Alkaline phosphatase; HDLC: High-density lipoprotein cholesterol; LDLC: Low-density lipoprotein cholesterol; CHD: Coronary heart disease; CKD: Chronic kidney disease; COPD: Chronic obstructive pulmonary disease; ACEI/ARB: Angiotensin-converting enzyme inhibitor/Angiotensin receptor blocker; CCB: Calcium channel blocker; NSAIDs: Non-steroidal anti-inflammatory drugs