Table 3.
Relative Risk of the Hemolytic–Uremic Syndrome among Children Infected with Escherichia coli O157:H7.
| Covariate* | Univariate Relative Risk (95% CI)† | P Value | Adjusted Relative Risk (95% CI)‡ | P Value |
|---|---|---|---|---|
| Age (continuous) | 1.0 (0.8 to 1.3) | 0.95 | 1.1 (0.8 to 1.5) | 0.43 |
| 0 to 5 yr§ | 1.0 | 1.0 | ||
| >5 yr | 0.7 (0.2 to 2.8) | 0.57 | 1.1 (0.2 to 5.7) | 0.93 |
| Sex | ||||
| Male§ | 1.0 | 1.0 | ||
| Female | 1.0 (0.3 to 4.0) | 0.96 | 1.1 (0.2 to 5.0) | 0.95 |
| Presence of bloody diarrhea | 0.4 (0.1 to 2.2) | 0.26 | 0.4 (0.1 to 3.0) | 0.36 |
| Presence of vomiting | 2.6 (0.5 to 13.3) | 0.25 | 3.2 (0.5 to 20.6) | 0.21 |
| Presence of fever¶ | 5.0 (0.4 to 66.0) | 0.22 | 6.2 (0.2 to 169) | 0.23 |
| Temperature (continuous)|| | 1.9 (0.5 to 7.4) | 0.37 | 14.1 (0.5 to 419) | 0.13 |
| Initial serum urea nitrogen (continuous)** | 1.0 (0.9 to 1.1) | 0.73 | 1.1 (0.9 to 1.3) | 0.53 |
| 2–10 mg/dl§ | 1.0 | 1.0 | ||
| ≥11 mg/dl | 2.2 (0.6 to 8.6) | 0.25 | 2.8 (0.5 to 14.4) | 0.23 |
| Initial serum creatinine (continuous)†† | 0.7 (0.01 to 91.5) | 0.89 | 4.7 (0.01 to >500) | 0.62 |
| 0.1–0.5 mg/dl§ | 1.0 | 1.0 | ||
| ≥0.6 mg/dl | 1.2 (0.1 to 11.9) | 0.85 | 3.0 (0.1 to 69.4) | 0.50 |
| Initial white-cell count (continuous) | 1.3 (1.1 to 1.5) | 0.005 | 1.5 (1.1 to 2.1) | 0.02 |
| 3200–12,900/mm3§ | 1.0 | 1.0 | ||
| ≥13,000/mm3 | 3.9 (1.0 to 15.5) | 0.06 | 6.0 (1.2 to 29.8) | 0.03 |
| Day initial white-cell count obtained | 0.5 (0.3 to 0.8) | 0.009 | 0.7 (0.4 to 1.5) | 0.38 |
| Day stool culture obtained | 0.3 (0.2 to 0.8) | 0.01 | 0.3 (0.1 to 0.7) | 0.008 |
| Day stool culture positive | 0.5 (0.3 to 1.0) | 0.04 | 1.0 (0.5 to 2.1) | 1.00 |
| Acetaminophen given | 3.9 (0.8 to 19.3) | 0.09 | 2.0 (0.3 to 12.9) | 0.46 |
| Antimotility drugs given | 2.8 (0.6 to 13.3) | 0.19 | 3.0 (0.5 to 19.4) | 0.25 |
| Antibiotics given | ||||
| Within first 7 days after onset of illness | 14.3 (2.9 to 70.7) | 0.001 | 17.3 (2.2 to 137) | 0.007 |
| Within first 3 days after onset of illness | 15.0 (1.3 to 174) | 0.03 | 32.3 (1.4 to 737) | 0.03 |
Continuous covariates were analyzed and reported on continuous scales and are also presented as dichotomous groupings around the median. CI denotes confidence interval.
Odds ratios were used to estimate relative risk.
The relative risk was adjusted for the initial white-cell count and the interval from the onset of diarrhea to the day on which the stool culture was obtained.
This category served as the reference group.
The category of fever was based on the caregivers’ reports and was added to the standardized questionnaire on December 1, 1998; thus, data on only 24 children were included in the analysis.
The initial temperature was documented in 18 children who presented to Children’s Hospital and Regional Medical Center in Seattle (2 of whom had the hemolytic–uremic syndrome).
To convert values for serum urea nitrogen to millimoles per liter, multiply by 0.357.
To convert values for serum creatinine to micromoles per liter, multiply by 88.4.