Predicting Sepsis-Related Mortality: Pitt Bacteremia Score is Superior to the Charlson Comorbidity Index

Abstract

Aim: To assess the role of Pitt bacteremia score (PBS) and Charlson Comorbidity Index (CCI) in predicting mortality among patients with intensive care unit (ICU)–acquired Gram-negative bacterial sepsis and to investigate other factors associated with mortality.

Methods: This retrospective study was carried out between January 2018 and January 2023. Patients diagnosed with ICU-acquired sepsis caused by Gram-negative bacteria were included in the study. Demographics, laboratory data, blood culture results, management, length of ICU stay, mortality, and other clinical data were recorded. PBS and CCI score were calculated based on data collected at time of blood withdrawal. The primary endpoint was mortality in ICU.

Results: Among the 425 patients included in the study, mortality was observed in 268 (63%). Age and sex were distributed similarly in the mortality and survival groups. CCI score with a cutoff value of > 5.5 (AUC = 0.611) and PBS with a cutoff value of > 2.5 (AUC = 0.904) were able to significantly predict mortality. Multivariable logistic regression revealed that mortality was independently associated with having any comorbidity, congestive heart failure, low platelet count, high lactate, high (> 2.5) PBS, and carbapenem resistance (p = 0.001).

Conclusion: PBS was more successful than CCI in predicting mortality in patients with ICU-acquired sepsis caused by Gram-negative bacteria. In addition to higher PBS, having any comorbidity (and additionally, congestive heart failure), lower platelet, higher lactate, and carbapenem resistance were risk factors for mortality.