COMBINED PREDICTIVE VALUE OF SOFA SCORE AND ADMISSION LACTATE FOR IN-HOSPITAL MORTALITY IN SEPTIC PATIENTS

Background: Sepsis remains a major cause of preventable hospital death, and early recognition of patients at greatest risk is central to timely resuscitation and critical care planning. The Sequential Organ Failure Assessment (SOFA) score measures the extent of acute organ dysfunction, whereas serum lactate reflects metabolic stress and impaired tissue perfusion. Although both are established prognostic indicators, the additional value obtained by combining them at admission has not been fully defined, particularly in resource-constrained hospitals. Objective: To assess the individual and combined predictive value of admission SOFA score and serum lactate for in-hospital mortality in adults with sepsis. Methods: This hospital-based observational analytical study included 210 adults fulfilling Sepsis-3 criteria who were managed in the emergency department, medical ward, or medical intensive care unit of Jinnah Postgraduate Medical Centre. Clinical and laboratory data were extracted from patient records using a structured proforma. The SOFA score and first lactate concentration obtained within 24 hours were analysed using multivariable logistic regression and receiver operating characteristic curves. Optimal thresholds were derived through the Youden index, and AUCs were compared using the DeLong test. Results: In-hospital mortality was 27.6%. Non-survivors had higher median SOFA scores than survivors, 8.5 versus 2.0, and higher lactate concentrations, 4.6 versus 2.4 mmol/L (both p < 0.001). Lactate independently predicted mortality (adjusted OR 1.54, 95% CI 1.13–2.08; p = 0.006), as did SOFA score (adjusted OR 1.28, 95% CI 1.13–1.45; p < 0.001). The AUC was 0.802 for lactate, 0.805 for SOFA, and 0.832 for the combined model. The combined model yielded 74.1% sensitivity, 81.6% specificity, 60.6% positive predictive value, and 89.2% negative predictive value. Its AUC was numerically higher than either marker alone, although the differences were not statistically significant. Conclusion: Admission SOFA score and serum lactate independently predicted in-hospital mortality, while their combined assessment provided the highest discrimination for practical early risk stratification. Keywords: Hospital Mortality; Lactic Acid; Logistic Models; Organ Dysfunction Scores; Prognosis; Sepsis; Shock, Septic.