Inflammatory and Nutritional Biomarkers Versus Clinical Scores in Predicting Mortality and Severity in Sepsis Patients

Sepsis is a life-threatening condition and a major global health burden, representing one of the leading causes of ICU admission worldwide . Despite advances in diagnosis and treatment, it remains associated with high mortality, particularly among critically ill and elderly patients, with an estimated 48 million cases and 11 million deaths globally in 2017 . Its defined as organ dysfunction caused by a dysregulated host response to infection; sepsis is a medical emergency requiring prompt recognition and early management . Survivors often experience long-term physical, cognitive, and psychological impairments, highlighting the need for early risk stratification and identification of patients at high risk to guide clinical decision-making and optimize ICU resource allocation .

Several clinical scoring systems have been developed to assess disease severity and predict mortality in septic patients. Among these, the Acute Physiology and Chronic Health Evaluation II (APACHE II) score is one of the most extensively validated tools and has demonstrated good discriminatory ability for predicting shortterm mortality in sepsis .

Similarly, the Sepsisrelated Organ Failure Assessment (SOFA) score is widely used for both the diagnosis and prognostic evaluation of sepsis in ICU settings. Its simplified version, the quick SOFA (qSOFA), is primarily utilized outside the ICU to identify patients at increased risk of poor outcomes and the need for prolonged ICU admission. However, while these scoring systems are useful, their predictive performance is not optimal when used in isolation, highlighting the need for complementary biomarkers .

In addition to clinical scores, hematological and immuno-inflammatory indices derived from the complete blood count (CBC) have emerged as valuable prognostic biomarkers . Red cell distribution width (RDW) has been independently associated with sepsis severity and mortality, with higher values observed in non-survivors .

Inflammatory ratios such as the neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and the systemic immune-inflammation index (SII) reflect systemic immune activation and have shown significant associations with adverse outcomes .