Table 4. Full Model and Final Determinants of Misdiagnosed Site of Infection .
| Variables | Full model OR (95% CI) | Reduced model ORa,b |
|---|---|---|
| Age (per decade) | 1.2 (1.1-1.3) | 1.1 |
| Sex (male) | 0.9 (0.7-1.3) | Not selected |
| Use of immunosuppressants | 1.1 (0.6-1.8) | Not selected |
| Use of antibiotics | 0.9 (0.6-1.3) | Not selected |
| Altered mental status | 1.0 (0.7-1.7) | Not selected |
| SBP | 1.0 (1.0-1.0) | Not selected |
| CRP | 1.0 (1.0-1.0) | Not selected |
| BF | 1.0 (1.0-1.0) | Not selected |
| Occurrence of Loeb criteria | 1.3 (0.8-2.2) | Not selected |
| Dementia | 1.9 (0.9-3.7) | 1.4 |
| Positive urine sediment test result without Loeb criteriac,d | 1.4 (0.9-2.1) | 1.1 |
| Site of infection at ED | ||
| Abdominal | 2.2 (1.3-3.7) | 1.4 |
| Bone and joint | 6.1 (2.8-13.4) | 3.4 |
| CNS | 11.0 (4.0-29.7) | 5.1 |
| Intravascular | 12.0 (5.3-27.2) | 6.7 |
| Respiratory | 1 [Reference] | 1 [Reference] |
| Urogenital | 1.6 (1.0-2.7) | 1.2 |
| Skin and soft tissue | 1.1 (0.5-2.2) | 1.0 |
Abbreviations: BF, breathing frequency; CNS, central nervous system; CRP, C-reactive protein; ED, emergency department; OR, odds ratio; SBP, systolic blood pressure.
a
Model selection is achieved by shrinkage, so the ORs with CIs cannot be determined.
b
The tuning parameter (λ) is chosen by cross-validation.25 The value of λ that gives the simplest model but also lies within 1 SE of the optimal value of λ was selected.
c
The Loeb criteria are dysuria, suprapubic pain or tenderness, frequency, or urgency. A positive urine sediment test result indicates nitrite positive or more than 5 white blood cells per high-power field.
d
Occurred in 36 of 163 misdiagnosed patients (22.1%) and 183 of 1267 nonmisdiagnosed patients (14.4%).