Abstract
PURPOSE: This study aims to explore the predictive value of macrophage inflammatory protein 3β (MIP-3β) for mortality risk in sepsis patients. METHODS: 177 sepsis patients visited the emergency medicine department of Beijing Chaoyang Hospital between October 2020 and April 2021. Within 1 h of admission, serum levels of WBC (white blood cell), PLT (platelet), TBIL (total bilirubin), PCT (procalcitonin), CRP (C-reactive protein), and MIP-3β were measured, and patients were assessed with organ failure scores—SOFA (Sequential Organ Failure Assessment) and APACHE II (Acute physiology and chronic health evaluation) scores. Logistic regression was used to predict independent risk factors for 28-day mortality, and Receiver Operating Characteristic (ROC)curves were used to assess predictive value. The categorical net reclassification improvement (NRI) was calculated to assess the incremental predictive value of adding MIP-3β to the SOFA score. RESULTS: MIP-3β (pg/mL), SOFA, and APACHE II scores were significantly higher in non-survivors compared to survivors (P < 0.05). The logistic regression analysis revealed that the MIP-3β, SOFA, and APACHE II scores were independent risk factors for 28-day mortality (P < 0.05) in sepsis patients. The area under the ROC curve (AUC) for the MIP-3β was 0.635 (sensitivity 0.573, specificity 0.679, critical value 93.43), indicating modest predictive value, lower than SOFA score 0.839 (sensitivity 0.573, specificity 0.962, critical value 7.5, Z = 3.446, P = 0.0006) and APACHE II score 0.773 (sensitivity 0.556, specificity 0.925, critical value 21.5, Z = 2.304, P = 0.0212); however, the combined prediction using MIP-3β and SOFA scores (AUC area 0.86, sensitivity 0.637, specificity 0.981, Z = 4.552, P < 0.0001) had higher AUC area, sensitivity, and specificity than MIP-3β alone (Table 3). Furthermore, adding MIP-3β to the SOFA score yielded a significant categorical NRI of 0.062 (95% CI: 0.023–0.107, P < 0.01), calculated using pre-specified risk categories of < 10%, 10–50%, and > 50% for 28-day mortality risk, indicating improved risk stratification. CONCLUSIONS: MIP-3β is an independent risk factor for 28-day mortality in sepsis, with higher levels associated with increased risk of death. While MIP-3β alone has modest predictive value, its combination with the SOFA score significantly improves mortality prediction, highlighting its potential role as a complementary biomarker for early risk stratification in sepsis. CLINICAL TRIAL NUMBER: Not applicable. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12879-026-12723-x.