Generalized Linear Mixed-Effects Model to Predict Hospitalization
| Predictor | Adjusted Odds Ratio (95% CI) | P |
|---|---|---|
| Demographic | ||
| Agea | <.001b | |
| 29–56 d | 0.11 (0.06–0.22) | <.001b |
| 57–90 d | 0.07 (0.03–0.14) | <.001b |
| Gestational agec | .02b | |
| <37 weeks' gestation | 1.64 (0.80–3.38) | .18 |
| Unknown | 0.38 (0.17–0.87) | .02b |
| History of chronic illness | 2.27 (0.85–6.07) | .10 |
| History of presenting illness | ||
| Decreased urine output | 4.13 (1.88–9.07) | <.001b |
| Ear discharge | 1.97 (1.17–3.31) | .01b |
| New difficulty feeding | 1.36 (0.81–2.30) | .25 |
| Diarrhea | 0.58 (0.21–1.59) | .29 |
| Physical examination | ||
| Respiratory distress | 40.54 (19.17–85.70) | <.001b |
| Dehydration | 2.89 (0.87–9.61) | .08 |
| Ill appearance | 1.64 (0.52–5.18) | .40 |
| Diagnostic test | ||
| Complete blood countd | <.001b | |
| Completed and within normal limits | 10.95 (5.95–20.15) | <.001b |
| Completed and abnormal | 9.25 (4.04–21.14) | <.001b |
| Urinalysise | .05 | |
| Completed and within normal limits | 2.11 (1.15–3.87) | .02 |
| Completed and abnormal | 2.14 (0.49–9.26) | .31 |
↵a Reference group: 0 to 28 d old.
↵b µStatistical significance (P < .05). In this model, age, gestational age, history of decreased urine output, history of ear discharge, respiratory distress on examination, and completion of complete blood count were independently associated with hospitalization. In the subanalysis including only the 1459 infants meeting simplified AAP diagnostic criteria (data available on request), the following differences were observed: chronic illness was not included in the model (univariable P > .1) and dehydrated appearance was statistically significant in the regression model (P = .02).
↵c Reference group: ≥37 wk gestation.
↵d Reference group: complete blood count not obtained. Test was considered abnormal if the WBC count was <5 or >15 × 103 cells/µL.
↵e Reference group: urinalysis not obtained. Test was considered abnormal if any of the following was present: leukocyte esterase, nitrite, or >5 WBCs per high-power field.