Background: Sepsis remains a critical public health concern, marked by elevated mortality rates and a multifaceted clinical course. Identifying reliable predictors of patient outcomes is imperative for optimizing the care of septic individuals. Existing clinical parameters and scoring systems have demonstrated varying degrees of predictive accuracy in septic patients.

Objective: To investigate the individual and combined predictive utility of modified shock index (MSI) and red cell distribution width (RDW) in septic patients admitted to the medical critical care unit of Black Lion Specialized Hospital in Addis Ababa, Ethiopia.

Methods: A retrospective observational study spanning four months (October 1, 2023GC, to January 2024GC) involved a systematic review of historical medical records for adult septic patients admitted to the medical ICU from January 2019 to December 2023.

Results: The study revealed a significant association between MSI and mortality; an MSI >1 was associated with a 67.5% decrease in survival odds compared to MSI <0.7 (p=0.009, OR=0.425). RDW >14.5% was associated with 2.69 times higher odds of mortality than RDW <14.5% (p=0.004, OR=2.69). The Modified SOFA is also associated with mortality, with higher scores (8-11 and >11) indicating an elevated risk of mortality (Exp(B) = 3.224, 95% CI [1.441, 7.212] and (Exp(B) = 13.736, 95% CI [4.787, 39.412]) respectively. Combining MSI and RDW improved mortality prediction in septic patients. 

Conclusion: Our analysis identifies gender, modified SOFA score, MSI, and RDW as critical determinants of sepsis-related mortality. The combined consideration of MSI and RDW enhances mortality prediction.