Table 1.
Baseline characteristics of the study population.
| Variable | Overall (n = 51) | AKI ** (n = 28) | Non-AKI (n = 23) | p |
|---|---|---|---|---|
| Age, years * | 53 (40–61) | 56 (40.5–61.5) | 51 (40–55) | 0.12 |
| Male (n (%)) | 30 (58.8) | 19 (68) | 11 (47) | 0.14 |
| BMI, kg/m2 * | 29.3 (25.9–31.6) | 16 (57) | 14 (46.7) | 0.71 |
| Comorbidities | ||||
| Obesity (n (%)) | 21 (41.2) | 12 (43) | 9 (39) | 0.78 |
| Diabetes (n (%)) | 16 (31.4) | 8 (28) | 8 (35) | 0.63 |
| Hypertension (n (%)) | 14 (27.5) | 12 (42) | 2 (8.7) | 0.01 |
| 2 ≥ comorbidities (n (%)) | 21 (41.2) | 14 (50) | 7 (30.4) | 0.15 |
| Critical care variables | ||||
| IMV (n (%)) | 32 (62.7) | 20 (71.4) | 12 (52.2) | 0.15 |
| PaO2/FiO2 ratio, mmHg * | 141 (108–187) | 139 (101–162) | 167 (132–220) | 0.06 |
| PEEP, cm H2O * | 10 (9.5–14) | 10 (10–14) | 10 (10–12) | 0.79 |
| pH * | 7.41 (7.33–7.44) | 7.39 (7.34–7.44) | 7.41 (7.33–7.46) | 0.53 |
| pCO2, mmHg * | 38.0 (32.3–51.9) | 42.1 (35–52.5) | 37.5 (25–47) | 0.15 |
| SOFA score, points * | 4 (2–6) | 4 (3–7) | 3 (2–6) | 0.01 |
| Treatments | ||||
| Vasoactive drugs (n (%)) | 16 (31.4) | 10 (62.5) | 6 (26) | 0.46 |
| Inotropic drug (n (%)) | 2 (3.9) | 1 (50) | 1 (4.3) | 0.88 |
| Systemic steroids (n (%)) | 25 (49) | 13 (52) | 12 (52) | 0.68 |
| Hydroxychloroquine (n (%)) | 7 (13.7) | 5 (71.4) | 2 (8.69) | 0.34 |
| Lopinavir/Ritonavir (n (%)) | 12 (23.5) | 4 (33.3) | 8 (34.7) | 0.08 |
| Nephrotoxic drugs (n (%)) | 1 (2) | 0 (0.0) | 1 (4.34) | 0.26 |
| Renal function indicators | ||||
| Serum creatinine, mg/dL, Day 1 * | 0.60 (0.50–0.72) | 0.61 (0.51–0.76) | 0.60 (0.49–0.70) | 0.58 |
| eGFR, mL/min/1.73m2, Day 1 * | 112.38 (98.45–121.40) | 113 (96–118) | 111 (106–124) | 0.73 |
| Serum creatinine, mg/dL, Day 5 * | 0.69 (0.54–0.88) | 0.79 (0.67–1.13) | 0.60 (0.51–0.75) | 0.01 |
| eGFR, mL/min/1.73m2, Day 5 * | 104 (90–117.50) | 99 (69.5–109.5) | 110 (103–121) | 0.01 |
| Final serum creatinine, mL/min * | 0.67 (0.55–0.97) | 0.74 (0.61–1.09) | 0.61 (0.52–0.76) | 0.13 |
| Final eGFR, mL/min/1.73m2 * | 104 (90–118-50) | 102 (88.5–113) | 107 (102–121) | 0.07 |
| Laboratories at Day 1 | ||||
| Hemoglobin, g/dL * | 13.3 (12.6–14.9) | 13.4 (12.5–15) | 13.3 (12.7–14.4) | 0.99 |
| Leucocytes, 10 ×3 mm3 * | 8.9 (6.3–13.4) | 9.3 (7.8–12.1) | 7.8 (5.1–13.5) | 0.22 |
| Lymphocytes, 10 ×3 mm3 * | 0.8 (0.6–1.0) | 0.8 (0.45–1) | 0.8 (0.65–1) | 0.37 |
| Platelets, 10 ×3 mm3 * | 272 (219–329) | 272 (216–362) | 272 (219–314) | 0.75 |
| Lactate dehydrogenase, U/mL * | 387 (299–557) | 386 (314–544) | 397 (265–572) | 0.37 |
| Total bilirubin, mg/dL * | 0.47 (0.37–0.63) | 0.56 (0.40–0.88) | 0.43 (0.34–0.54) | 0.07 |
| Creatine phosphokinase, U/L * | 140 (39–443) | 224.5 (79.5–739.5) | 60 (35.5–291) | 0.02 |
| D-dimer, µg/mL * | 0.91 (0.42–2.50) | 1.08 (0.55–4.27) | 0.49 (0.34–1.29) | 0.04 |
| C-reactive protein, mg/dL * | 16.5 (10–27.6) | 18 (13–31.9) | 13.2 (10–22.4) | 0.05 |
| Fibrinogen, mg/dL * | 734 (580–821) | 742 (604–805) | 685 (565–786) | 0.41 |
| Procalcitonin, ng/mL * | 0.39 (0.11–0.92) | 0.62 (0.35–1.26) | 0.14 (0.08–0.34) | 0.01 |
| Troponin, pg/mL * | 5.6 (3.3–37) | 11.8 (3.8–37) | 3.9 (1.5–9) | 0.04 |
| Ferritin, ng/mL * | 745 (358–1883) | 710 (304–2491) | 756 (457–953) | 0.83 |
| Urinary kidney biomarkers | ||||
| TIMP-2, ng/mL, Day 1 * | 5.64 (3.03–9.02) | 6.16 (3.49–9.66) | 5.07 (3.01–7.24) | 0.26 |
| TIMP-2, ng/mL, Day 5 * | 5.21 (3.31–7.81) | 4.16 (3.18–7.36) | 5.26 (3.65–12.03) | 0.11 |
| IGFBP7, ng/mL/1000, Day 1 * | 13.83 (8.60–24.65) | 17.43 (9.35–30.20) | 12.50 (7.04–19.92) | 0.12 |
| IGFBP7, ng/mL/1000, Day 5 * | 22.75 (12.63–46.20) | 28.44 (13.05–77.78) | 16.53 (11.93–32.35) | 0.22 |
| [TIMP2] × [IGFBP7], (ng/mL)2/1000, Day 1 * | 0.085 (0.05–0.24) | 0.16 (0.05–0.32) | 0.07 (0.04–0.11 | 0.04 |
| [TIMP2] × [IGFBP7], (ng/mL)2/1000, Day 5 * | 0.14 (0.05–0.28) | 0.13 (0.05–0.32) | 0.14 (0.06–0.19) | 0.99 |
| NGAL, ng/mL, Day 1 * | 39.3 (19.2–98.5) | 54.70 (36.40–117.40) | 32.40 (14–40.05) | 0.00 |
| NGAL, ng/mL, Day 5 * | 33 (14–106.2) | 35.20 (17.55–118.95) | 20.50 (11.45–52.50) | 0.07 |
| Outcomes | ||||
| Day in hospital | 16 (12–27) | 20.5 (14.5–28) | 13 (10.5–22.5) | 0.03 |
| Days on IMV | 13 (10–22.2) | 13 (12–22) | 10.5 (8–26) | 0.43 |
| Mortality (n (%)) | 10 (19.6) | 7 (25) | 3 (13) | 0.28 |
Acute kidney injury (AKI); body mass index (BMI); invasive mechanical ventilation (IMV); partial arterial oxygen pressure/inspired oxygen fraction (PaO2/FiO2); partial pressure of carbon dioxide (pCO2); positive end-expiratory pressure (PEEP); sequential organ failure assessment (SOFA); estimated glomerular filtration rate (eGFR); Systemic steroids: dexamethasone, methylprednisolone; prednisone; neutrophil gelatinase-associated lipocalin (NGAL); tissue inhibitor of metalloproteinases-2 (TIMP-2); insulin-like growth factor binding protein 7 (IGFBP7). * Data are expressed as medians (interquartile ranges). Comparisons of the AKI group vs. the non-AKI group were made using the chi-squared test for categorical variables and Mann–Whitney U for continuous variables. Bold values denote statistical significance at the p ≤ 0.05 level. ** Diagnosis and staging of AKI were based on the Kidney Disease Improving Global Outcomes (KDIGO) criteria using serum creatinine (sCr) levels and urine output [12].