Performance of various pneumonia severity models for predicting adverse outcomes in elderly inpatients with community-acquired pneumonia.

OBJECTIVE: We aimed to assess the performance of common pneumonia severity scores, such as pneumonia severity index (PSI), CURB-65, CRB-65, A-DROP, and SMART-COP, in predicting adverse outcomes in elderly community-acquired pneumonia cohort and to determine the optimal scoring system for specific outcomes of interest.

METHODS: A total of 822 elderly inpatients were included in the retrospective cohort study. Clinical and laboratory results on admission were used to calculate the above scores. The primary outcome was 30-day mortality. Secondary outcomes were in-hospital mortality, need for mechanical ventilation (MV) and ICU admission. Model discrimination was evaluated by the area under receiver operating characteristic curves (AUCs).

RESULTS: The 30-day and in-hospital mortality rates were 6.8% (56/822) and 8.6% (71/822), respectively. One hundred and ninety-eight (24.0%) received MV and 111 (13.5%) were admitted to the ICU. All five scoring systems showed the same trend of increasing rates of each adverse outcome with increasing risk groups (all p < 0.001). PSI had the highest AUC, sensitivity, and negative predictive value (NPV) in predicting 30-day mortality and in-hospital mortality. SMART-COP had the highest AUC for predicting the need for MV and ICU admission, but PSI had the highest sensitivity and NPV for these two outcomes.

DISCUSSION: PSI performed well in identifying elderly patients at risk for 30-day mortality and its high NPV is helpful in excluding patients who are not at risk. Considering their effectiveness and simplicity, SMART-COP and CURB-65 are easier to perform in clinical practice than PSI.