Table 2.
Multivariable Proportional Odds Logistic Regression for Disease Severity (Full Model)
| Potential Predictor | Adjusted pOR (95% CI)a |
|---|---|
| Age, y | |
| 1 | 1.28 (.89–1.85) |
| 2 | 1.19 (.91–1.56) |
| 5 | Ref. |
| 10 | 1.04 (.82–1.32) |
| Male sex | 0.79 (.59–1.06) |
| Nonwhite race | 0.66 (.48–.92)c |
| Smoke exposure | 0.85 (.63–1.14) |
| Prior pneumonia | |
| None | Ref. |
| Not hospitalized | 1.17 (.77–1.78) |
| Hospitalized | 1.71 (1.03–2.84)c |
| Asthma | 0.90 (.64–1.27) |
| Prematurity | 1.15 (.79–1.66) |
| Season | |
| Winter | Ref. |
| Spring | 1.24 (.84–1.83) |
| Summer | 0.80 (.50–1.29) |
| Fall | 1.05 (.73–1.53) |
| Days of illness | |
| 1 | 0.97 (.77–1.22) |
| 3 | 0.99 (.88–1.10) |
| 5 | Ref. |
| 10 | 0.99 (.82–1.20) |
| Fever at home | 1.01 (.55–1.85) |
| Decreased oral intake | 1.21 (.89–1.65) |
| Difficulty breathing | 1.09 (.68–1.76) |
| Rapid breathing | 1.07 (.70–1.64) |
| Wheezing at home | 0.76 (.54–1.07) |
| Vomiting | 1.14 (.85–1.53) |
| Abdominal pain | 1.36 (.81–2.37) |
| Temperature, ºC | |
| 37 | Ref. |
| 38 | 0.95 (.71–1.28) |
| 39 | 0.93 (.61–1.41) |
| 40 | 0.96 (.56–1.66) |
| RR (50th vs 95th percentile) | 2.43 (1.50–3.93)c |
| HR (50th vs 95th percentile) | 1.61 (.88–2.96) |
| SBP (50th vs 5th percentile) | 2.08 (1.23–3.51)c |
| PF ratiob | |
| 450 | Ref. |
| 400 | 2.52 (1.89–3.38)c |
| 300 | 3.66 (2.38–5.61)c |
| 200 | 2.84 (1.87–4.31)c |
| Retractions | 1.95 (1.32–2.87)c |
| Grunting | 1.77 (1.05–2.98)c |
| Nasal flaring | 1.27 (.80–2.00) |
| Crackles | 0.91 (.66–1.27) |
| Rhonchi | 1.20 (.87–1.66) |
| Wheezing | 0.80 (.54–1.19) |
| Decreased breath sounds | |
| Not decreased | Ref. |
| Focally decreased | 1.18 (.82–1.69) |
| Diffusely decreased | 1.30 (.82–2.06) |
| Abnormal skin color | 1.16 (.70–1.90) |
| Capillary refill ≥3 sec | 1.99 (1.30–3.03)c |
| Chest radiography findings | |
| No atelectasis or pneumonia | Ref. |
| Favoring atelectasis | 1.90 (1.28–2.80)c |
| Atelectasis vs pneumonia | 2.25 (1.12–4.52)c |
| Favoring pneumonia | 2.53 (1.54–4.17)c |
| Laterality/lobar involvement | |
| None | Ref. |
| Unilateral and single lobe | 2.02 (1.26–3.15)c |
| Unilateral and multifocal | 2.51 (1.29–4.75)c |
| Bilateral/multifocal | 2.08 (1.42–3.05)c |
| Pleural effusion | 2.35 (1.37–4.04)c |
| Hyperinflation | 1.55 (1.08–2.23)c |
| Airways (ie, peribronchial) involvement | 0.85 (.60–1.22) |
| Model performance | |
| C-index | 0.84 (.818–.862) |
| C-index (bootstrapped) | 0.812 |
| AIC | 1423.8 |
| Observed/predicted intercept | –0.06 |
| Observed/predicted slope | 0.88 |
Abbreviations: AIC, Akaike information criterion; CI, confidence interval; HR, heart rate; PF, partial pressure of oxygen/fraction of inspired oxygen; pOR, proportional odds ratio; RR, respiratory rate; SBP, systolic blood pressure.
aProportional odds ratios are interpreted as the odds of developing moderate or severe disease compared to the referent group. For example, a child with radiographic pneumonia had 2.53 times the odds of developing moderate or severe disease compared with those with no atelectasis or pneumonia on chest radiography.
bTo evaluate both oxygen saturation and oxygen requirement, oxygenation was reported using the oxygen saturation/fraction of inspired oxygen (FiO2) ratio, which is a noninvasive proxy for partial pressure of oxygen/FiO2 [15–17].
c P < .05.