Table 2.
Demographic, Laboratory, and Clinical Continuous Variables in the Oligoanuric and Nonoligoanuric Groups
| Variable | Median (Range) [IQR]
|
U | Effect Size (r)a | P Value | ||
|---|---|---|---|---|---|---|
| All Patients (n = 50) | Anuric Patients (n = 34) | Nonoligoanuric Patients (n = 16) | ||||
| Age, y | 4.1 (1.0 to 17.2) [5.5] | 3.9 (1.0 to 13.4) [4.6] | 5.3 (1.2 to 17.2) [8.3] | 228 | −0.13 | .36 |
| Duration of illness at first symptom, d | ||||||
| Bloody stoolb | 3 (1 to 5) [2] | 3 (1 to 5) [2] | 3 (1 to 4) [1.5] | 186.5 | −0.04 | .8 |
| Evaluated | 3 (1 to 8) [2] | 3 (1 to 8) [3] | 2.5 (1 to 5) [1] | 183.5 | −0.27 | .06 |
| Intravenous fluid | 4 (1 to 15) [3] | 5 (1 to 11) [3] | 3.5 (1 to 15) [3.3] | 207.5 | −0.19 | .18 |
| Blood test | 4 (1 to 15) [2] | 4 (1 to 11) [2] | 3 (1 to 15) [1.8] | 191 | −0.24 | .09 |
| Stool culture | 4 (1 to 21) [2.3] | 4 (1 to 10) [3] | 3.5 (1 to 21) [2.5] | 213.5 | −0.17 | .22 |
| Initial laboratory values | ||||||
| WBC, No./mm3 | 14.5 (5.2 to 44.7) [11.1] | 15.4 (5.2 to 44.7) [12.5] | 12.1 (8.1 to 22.1) [5.5] | 167.5 | −0.27 | .06 |
| Hematocrit, %c | 37.3 (12 to 49) [8.5] | 37.8 (13 to 47) [9.2] | 37.3 (12 to 49) [6.7] | 236.5 | −0.06 | .69 |
| Platelets, No. × 1000/mm3c,d | 257 (43 to 469) [211] | 249 (43 to 469) [216] | 275 (50 to 414) [191] | 204 | −0.11 | .44 |
| Sodium, mEq/Lc | 134 (121 to 144) [5] | 133 (121 to 144) [5] | 135 (130 to 141) [6] | 151 | −0.32 | .02 |
| Bicarbonate, mEq/Lc | 20 (7 to 29) [7] | 20.5 (7 to 29) [8.3] | 19 (11.7 to 27) [6] | 246 | −0.028 | .85 |
| Urea nitrogen, mg/dLc | 16.5 (4 to 280) [37.1] | 17.3 (4 to 273) [41] | 15.5 (7 to 280) [21] | 224.5 | −0.095 | .51 |
| Creatinine, mg/dLc | 0.5 (0.2 to 22.3) [1.7] | 0.6 (0.3 to 22.3) [2.4] | 0.4 (0.2 to 17.5) [0.5] | 206 | −0.15 | .29 |
| Sodium level on day HUS diagnosed, mEq/Lc | 134 (121 to 147) [6] | 133 (121 to 143) [6.3] | 135 (129 to 147) [6.5] | 180 | −0.27 | .06 |
| Duration, d | ||||||
| Dialysis | 5 (0 to >50) [13] | 11.5 (0 to >50) [11] | 0 (0 to 4) [0] | 33 | −0.71 | <.001 |
| Anuriae | 1 (0 to 45) [4] | 3 (1 to 45) [5.5] | 0 | 16 | −0.78 | <.001 |
| Hospital stay | 14 (4 to 82) [11] | 18 (7 to 82) [9] | 9 (4 to 16) [5] | 67 | −0.6 | <.001 |
Abbreviations: HUS, hemolytic uremic syndrome; IQR, interquartile range; WBC, white blood cells.
SI conversion factors: To convert bicarbonate to millimoles per liter, multiply by 1.0; creatinine to micromoles per liter, multiply by 88.4; hematocrit to proportion of 1.0, multiply by 0.01; and sodium to millimoles per liter, multiply by 1.0.
Medium effect is defined as r > |0.3|.
Of the 42 subjects with this history.
Laboratory data were not available for 1 nonoligoanuric patient until transfer to one of the study sites several days after onset of HUS.
Platelet count not available for 1 additional nonoligoanuric patient early in illness, but other laboratory values are included.
Precise day of onset of anuria not determined for 1 patient.