Table 2.
Characteristics of study population
| Prerenal (n = 34) | Intrinsic (n = 52) | P | |
|---|---|---|---|
| Female | 6 (17.6%) | 27 (51.9%) | <0.01 |
| Male | 28 (82.4%) | 25 (48.1%) | |
| Age (years) | 68.4 ± 14.1 | 70.5 ± 16.5 | 0.53 |
| Body mass index (kg/m2) | 26.4 ± 4.9 | 26.1 ± 4.5 | 0.76 |
| Preexisting CKD | 14 (41.2%) | 26 (50%) | 0.51 |
| Biopsy | 1 (2.9%) | 8 (15.4%) | 0.08 |
| Origin of AKI | |||
| dehydration by gastroenteritis | 12 (35.3%) | ||
| hemodynamic, drug-induced (diuretics, ACE-I, ARB, NSAID) | 11 (32.4%) | ||
| other causes of dehydration | 5 (14.7%) | ||
| cardiorenal syndrome | 2 (5.9)% | ||
| hepatorenal syndrome | 1 (2.9%) | ||
| bilateral renal artery stenosis | 1 (2.9%) | ||
| short-term hypotension | 2 (5.9%) | ||
| hypotension-induced acute tubular necrosis | 4 (7.7%) | ||
| toxic acute tubular necrosis | 2 (3.8%) | ||
| crescentic glomerulonephritis | 3 (5.8%) | ||
| lupus nephritis | 2 (3.8%) | ||
| other forms of glomerulonephritis | 4 (7.7%) | ||
| thrombotic thrombocytopenic purpura | 1 (1.9%) | ||
| drug-induced acute interstitial nephritis | 3 (5.8%) | ||
| renal infarction | 1 (1.9%) | ||
| rhabdomyolysis | 1 (1.9%) | ||
| urosepsis/severe urinary tract infection | 22 (42.3%) | ||
| contrast-media induced | 3 (5.8%) | ||
| multiple myeloma | 1 (1.9%) | ||
| unknown | 5 (9.6%) | ||
| Concomitant diseases | |||
| diabetes mellitus | 10 (29.4%) | 15 (28.8%) | 1.0 |
| hypertension | 29 (85.3%) | 36 (69.2%) | 0.12 |
| urinary tract infection | 0 (0%) | 23 (44.2%) | <0.01 |
| Medication on admission | |||
| ACE-I/ARB | 19 (55.9%) | 17 (32.7%) | 0.07 |
| diuretics | 23 (67.6%) | 22 (42.3%) | 0.04 |
| eGFR on admission (ml/min per 1.73 m2) | 18.2 ± 9.9 | 19.9 ± 13.4 | 0.52 |
| creatinine on admission (mg/dl) | 4.4 ± 2.7 | 4.1 ± 2.2 | 0.55 |
| creatinine prior to admission (mg/dl, if available) | 1.4 ± 0.7 | 1.4 ± 0.8 | 0.88 |
| creatinine at discharge (mg/dl) | 1.7 ± 0.9 | 2.2 ± 1.6 | 0.047 |
| proteinuria (mg/L) | 98 (66 to 178) | 393 (167 to 1023) | <0.01 |
| proteinuria (mg/L)/urinary creatinine (g/L) | 165 (75 to 309) | 987 (295 to 2071) | <0.01 |
| C-reactive protein (mg/dl) | 5.2 ± 4.6 | 6.7 ± 9.7 | 0.40 |
| urinary creatinine (g/L) | 0.71 ± 0.32 | 0.61 ± 0.38 | 0.23 |
| urinary sodium (mmol/L) | 67.0 ± 32.4 | 67.5 ± 39.4 | 0.95 |
| plasma sodium (mmol/L) | 137.6 ± 4.5 | 137.4 ± 5.5 | 0.90 |
| fractional excretion of sodium (%) | 3.5 ± 2.5 | 5.2 ± 6.5 | 0.10 |
| urinary calprotectin (ng/ml) | 28 (13 to 73) | 1692 (765 to 4735) | <0.01 |
| urinary calprotectin (ng/ml)/urinary creatinine (g/L) ratio | 52 (23 to 123) | 3698 (1330 to 7812) | <0.01 |
The numeric data are presented as means ± standard deviation in case of normal distribution, otherwise as median and interquartile range (calprotectin, calprotectin/creatinine ratio, and proteinuria). Statistical tests used for the individual parameters are presented in the statistics section. P < 0.05 was regarded as statistically significant. CKD, chronic kidney disease; AKI, acute kidney injury; ACE-I, angiotensin-converting enzyme inhibitor; ARB, angiotensin-receptor blocker; NSAID, nonsteroidal anti-inflammatory drug; eGFR, estimated GFR.