Main findings
pneumonia, acute illness
PNEUMONIA
In this study, we performed an external validation of four CPMs for SI in 8211 children from 1 month to 16 years presenting with acute illness in ambulatory care. The multinomial LRMs Feverkidstool and Craig model showed varying C-statistics for the different outcomes ranging from 0.63 to 0.80. Predictions of pneumonia by Feverkidstool were well calibrated, but the other outcomes showed weak calibration. After the model update, Feverkidstool and the Craig model achieved good discriminative ability with C-statistics for the different outcomes ranging from 0.78 to 0.86 and good overall calibration. At low-risk cut-offs, however, sensitivities ranged from 0 to 0.71, and negative likelihood ratios ranged from 1 to 0.37, limiting the rule-out value for SBI. Specificity (> 0.97) and positive likelihood ratios (> 10.29) on the other hand were very high at higher-risk cut-offs. The models therefore seem more suited for ruling in than for ruling out SI in ambulatory care. The risk scores SBI score and PAWS performed very poorly in our cohort with extremely low sensitivities of 0.11 and 0.32, respectively. They appear unfit to effectively rule out SI in the ambulatory setting.