Procalcitonin as a Prognostic Predictor in Patients With Acute Infectious Disease Hospitalized in the Internal Medicine Department.

Procalcitonin is a biomarker used to distinguish between bacterial and viral infections, as well as to determine a patient's risk category and serve as a prognostic indicator. Furthermore, monitoring procalcitonin levels and analysing their kinetics during hospitalization improves the management of patients with sepsis and informs decision-making regarding antibiotic use. A wide range of studies has evaluated the diagnostic yield of procalcitonin in sepsis patients, demonstrating its superiority over CRP. However, the studies examined intensive care patients, trauma patients, surgical patients, or relatively young patients (mean age 69). There is significant heterogeneity among the studies, and they do not reach a definitive conclusion: some show an association between high procalcitonin levels and mortality, while others indicate that procalcitonin lacks independent prognostic value. Consequently, there is a significant gap in existing knowledge regarding the value of procalcitonin in a "real-life" setting-specifically, among elderly patients (over age 70) hospitalized in internal medicine wards. The investigators will identify all patients who underwent procalcitonin testing from 2020 onwards and were hospitalized in internal medicine or geriatric wards. Subsequently, the investigators will review medical records and extract relevant data regarding their disease course and outcomes.