Objective: Pneumonia is among the most common infectious causes of death worldwide. Mortality can reach up to 30% in pneumosepsis cases requiring intensive care unit(ICU) admission. In recent years, procalcitonin/albumin ratio(PAR) has emerged as an essential parameter for identifying critical patients. This study aimed to evaluate the role of PAR in predicting pneumosepsis in critical patients admitted to the ICU due to pneumonia.

Material and Method: This study was conducted retrospectively on 300 patients requiring ICU admission due to pneumonia between June 01, 2022 and November 15, 2023, at a training and research hospital anesthesia and chest diseases intensive care units. The patients sociodemographic charac-teristics and vital signs were obtained from the patients physical files, while laboratory results and radiological images were examined through the hospital\'s internal information management system (HIMS).

Results: Three hundred patients were included in the study. The mean age of the patients was 64.97±16.64. 107 (35.6%) of the patients included in the study were female. 217 (72.4%) of the patients included in the study had pneumosepsis. 21(11%) of the patients included in the study died within 30 days of follow-up. PAR was 0.31±0.82 in patients with pneumonia and 1.56±4.96 in patients with pneumosepsis. There was a significant differen-ce between the groups(p< 0.001). The cutoff value for PAR was determined as 0.042 with 73.3%sensitivity and 50.6%specificity. PAR was defined as a predictive factor of pneumosepsis (AUC 0.631 95%CI, 0.532-0.701; p< 0.001).

Conclusion: The procalcitonin to albumin ratio can be used to predict sepsis related mortality in intensive care unit patients with pneumonia admission.