Table 3.

Final Reduced Clinical Prediction Model for Disease Severity

Predictor	Adjusted pOR (95% CI)a
Respiratory rate (50th vs 95th percentile)	2.53 (1.63–3.93)
Systolic blood pressure (50th vs 5th percentile)	2.20 (1.34–3.61)
PF ratiob
450	Ref.
400	2.56 (1.94–3.38)
300	3.33 (2.22–4.49)
200	2.28 (1.59–3.28)
Retractions	2.06 (1.48–2.87)
Capillary refill ≥3 sec	2.47 (1.69–3.61)
Chest radiography findings
No atelectasis or pneumonia	Ref.
Favoring atelectasis	1.94 (1.36–2.75)
Atelectasis vs pneumonia	2.33 (1.21–4.49)
Favoring pneumonia	2.79 (1.77–4.41)
Pleural effusion	2.34 (1.39–3.92)
Model performance
C-index	0.82 (.796–.844)
C-index (bootstrapped)	0.81
AIC	1422.9
Observed/predicted intercept	–0.01
Observed/predicted slope	0.93

Abbreviations: AIC, Akaike information criterion; CI, confidence interval; PF, partial pressure of oxygen/fraction of inspired oxygen; pOR, proportional odds ratio.

^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 2.79 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].