| Variables | Percentage Antibiotic Prescription | Bivariate Analysis | Multivariate Analysis | ||||||
|---|---|---|---|---|---|---|---|---|---|
| If Characteristic Is Present | If Characteristic Is Absent | OR | 95% CI | P Value | Selection | OR | 95% CI | P Value | |
| Patient characteristics | |||||||||
| Age: 3–6 months | NA | NA | 0.15 | 0.03–0.63 | .01 | EA | 0.17 | 0.03–0.74 | .03 |
| 6–12 months | 0.71 | 0.41–1.23 | .22 | 1.03 | 0.55–1.94 | .93 | |||
| >12 months (reference group) | |||||||||
| Concerned parents at home visit | 36.1 (26/72) | 25.1 (89/354) | 1.70 | 0.99–2.91 | .05 | EA | 2.02 | 1.06–3.58 | .03 |
| Number of children in household | NA | NA | 1.25 | 1.00–1.56 | .05 | SS | 1.16 | 0.90–1.48 | .25 |
| Patient history (signs present at moment of contacting out-of-hours service) | |||||||||
| Duration of illness at presentation (days) | NA | NA | 1.08 | 1.02–1.14 | .01 | EA | 1.05 | 0.99–1.12 | .11 |
| Fever in previous week | 35.5 (22/62) | 24.4 (73/299) | 1.58 | 0.82–3.04 | .17 | EA | 1.15 | 0.52–2.57 | .73 |
| Fever in past 6 months | 29.6 (85/287) | 20.3 (31/153) | 1.67 | 1.04–2.66 | .03 | SS | 1.33 | 0.78–2.26 | .30 |
| Vaccination in previous week | 10.7 (3/28) | 27.6 (114/413) | 0.32 | 0.10–1.10 | .07 | SS | 0.34 | 0.08–1.38 | .13 |
| Decreased urine production | 35.7 (40/112) | 22.6 (66/292) | 1.84 | 1.16–2.91 | <.01 | SS | 2.00 | 1.17–3.41 | .01 |
| Physical examination | |||||||||
| Tachypnea | 19.1 (13/68) | 27.4 (75/274) | 0.71 | 0.36–1.40 | .33 | EA | 0.84 | 0.41–1.75 | .65 |
| Height of rectal temperature | NA | NA | 0.61 | 0.46–0.80 | <.01 | EA | 0.52 | 0.37–0.71 | <.01 |
| Ill appearance | 47.6 (20/42) | 24.4 (96/394) | 2.79 | 1.46–5.35 | <.01 | EA | 3.26 | 1.30–8.20 | .01 |
| YOS score | NA | NA | 1.08 | 0.99–1.18 | .07 | EA | 1.02 | 0.91–1.15 | .69 |
| Earache resulting in altered behavioral or sleeping pattern | 43.3 (13/30) | 25.1 (95/378) | 2.27 | 1.08–4.79 | .03 | SS | 2.59 | 1.06–6.30 | .04 |
| Signs of throat infection | 36.4 (40/110) | 17.3 (38/220) | 2.50 | 1.50–4.18 | <.01 | SS | 2.37 | 1.35–4.15 | <.01 |
| Runny nose (patient history) | 32.6 (46/141) | 23.2 (69/297) | 1.59 | 1.02–2.49 | .04 | SS | 1.57 | 0.94–2.60 | .08 |
Bold: multivariate P < .05. The physical examination forms included categorical variables with possible answers: “no, little, very, very much.” These variables were dichotomized using a cutoff point between “little” and “very.” Decreased urine production was considered if micturition was much decreased or if there was no micturition at all.
NA indicates not applicable; EA, expected association; SS, bivariate statistical significance; YOS, Yale Observation Scale.