Comparative analysis of APUA, APUA-RO₂, and CURB-65 scores for mortality risk in hospitalized pneumonia patients

Abstract

Background

Early identification of patients at high risk of mortality in community-acquired pneumonia (CAP) is critical for clinical decision-making. While the CURB-65 score is widely used, simplified tools such as APUA and APUA-RO₂ have been proposed to improve risk stratification by incorporating fewer and more accessible parameters.

Methods

This retrospective single-center study included adult patients (≥18 years) hospitalized with CAP between January 2023 and December 2024. The APUA, APUA-RO₂, and CURB-65 scores were calculated based on admission data. The primary outcome was 30-day in-hospital mortality. The predictive performances of the scores were compared using receiver operating characteristic (ROC) curve analysis, and AUCs were statistically compared using the DeLong test.

Results

A total of 348 patients were included; the in-hospital mortality rate was 32.5 %. The area under the curve (AUC) for APUA-RO₂ was 0.716 (95 % CI, 0.657–0.774), for CURB-65 was 0.716 (95 % CI, 0.662–0.770), and for APUA was 0.658 (95 % CI, 0.596–0.719). APUA-RO₂ showed significantly better discriminatory ability than APUA (P < .001). No significant difference was observed between APUA-RO₂ and CURB-65 (P = .976).

Conclusion

Both APUA-RO₂ and CURB-65 demonstrated moderate and comparable accuracy in predicting 30-day mortality in hospitalized CAP patients. The APUA-RO₂ score may be a practical alternative to existing tools, offering a balance between simplicity and prognostic utility.