Updating cut-off values of severity scoring systems for community-acquired pneumonia to orchestrate more predictive accuracy

Background: The assessment of severity is crucial in the management of community-acquired pneumonia (CAP). It remains unknown whether updating cut-off values of severity scoring systems orchestrate improvement in predictive accuracy. Methods: 3,212 patients with CAP were recruited to two observational prospective cohort studies. Three bettered scoring systems were derived from the corresponding well-established and extensively used pneumonia-specific severity scoring systems, i.e. pneumonia severity index, minor criteria and CURB-65 (confusion, urea >7 mmol/L, respiratory rate ≥30/min, low blood pressure, and age ≥65 years) score, with the updating cut-off values for tachypnea and low blood pressure. Cronbach α was employed to determine construct validity. Discrimination was valued by calculating the area under the receiver operating characteristic curve (AUROC) and net reclassification improvement (NRI). Results: Respiratory rate ≥22/min and systolic blood pressure ≤100 mm Hg were performed better than respiratory rate ≥30/min and hypotension for predicting mortality in the derivation cohort, respectively (AUROC, 0.823 vs 0.519, 0.688 vs 0.622; NRI, 0.61, 0.13). Bettered scoring systems orchestrated higher convergences, indicated by greater Cronbach α and more decrease in Cronbach α if the updating cut-off values were deleted. The six scoring systems agreed well with one another. Bettered- pneumonia severity index, minor criteria and CURB-65 score showed higher associations with severity and mortality rates and demonstrated greater predictive accuracies for mortality compared with the corresponding original systems (AUROC, 0.939 vs 0.883, 0.909 vs 0.871, 0.913 vs 0.859; NRI, 0.113, 0.076, 0.108; respectively). The validation cohort confirmed a similar pattern. Conclusions: KEY MESSAGES: Updating cut-off values were performed better for predicting mortality. Bettered scoring systems orchestrated higher convergences. Bettered scoring systems demonstrated greater predictive accuracies for mortality.