Are Inflammatory Biomarkers at ICU Discharge Still Predictive of Post-ICU Mortality in Sepsis and Septic Shock? A...

Background: Sepsis and septic shock are associated with high mortality in intensive care units (ICUs), with a substantial risk persisting after ICU discharge. However, it remains unclear whether inflammatory biomarkers retain their prognostic value at the time of ICU discharge. This study aimed to evaluate whether discharge inflammatory biomarkers-including neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), platelet-to-mean platelet volume ratio (PLT/MPV), and C-reactive protein-to-albumin ratio (CAR)-remain predictive of short- and long-term mortality in patients with sepsis and septic shock. Methods: In this single-center, retrospective cohort study, adult patients with sepsis or septic shock discharged from a tertiary ICU specializing in chest diseases between January 2013 and January 2015 were included. Sepsis and septic shock were retrospectively re-classified according to Sepsis-3 criteria. Inflammatory biomarkers measured at ICU admission and discharge, along with clinical variables and disease severity scores (APACHE II and SOFA), were recorded. Patients were followed for 28-day, 6-month, and 2-year mortality. The prognostic performance of biomarkers was assessed using receiver operating characteristic (ROC) analysis, and optimal cut-off values were determined. Independent predictors of mortality were evaluated using Cox proportional hazards regression analysis. Results: A total of 461 patients were included. In total, 291 (63.1%) had sepsis without shock and 170 (36.9%) had septic shock. The overall male proportion was 62%, with a median age of 65 (IQR 54-74) years in the sepsis group and 70 (63-79) years in the septic shock group. Mortality rates were significantly higher in patients with septic shock compared to those with sepsis at 28 days (24% vs. 10%, p < 0.001), 6 months (44% vs. 27%, p < 0.001), and 2 years (71% vs. 57%, p = 0.003). In unadjusted survivor/non-survivor comparisons, elevated discharge NLR and CAR were associated with early post-ICU mortality. However, in multivariable Cox regression, discharge NLR, but not discharge CAR, remained independently associated with 28-day and 6-month mortality. On ROC analysis, discharge NLR showed moderate discriminative performance for 28-day mortality (AUC 0.67, 95% CI 0.60-0.74), as did discharge CAR (AUC 0.68, 95% CI 0.60-0.76), although CAR did not retain independent prognostic significance after adjustment. An NLR value ≥ 5 was identified as an independent predictor of 28-day mortality (HR 2.44; 95% CI 1.24-4.80; p = 0.010) and was also significantly associated with 6-month mortality (HR 2.02; 95% CI 1.18-3.45; p = 0.011), although its predictive value decreased over longer follow-up periods (HR 1.37; 95% CI 0.93-2.01; p = 0.11 at 2 years). Conclusions: Inflammatory biomarkers measured at ICU discharge, particularly NLR, remain predictive of short-term mortality in patients with sepsis and septic shock, but their prognostic value diminishes over time. Assessment of inflammatory status at ICU discharge may provide a practical tool for early post-ICU risk stratification and may support clinical decisions regarding intensified outpatient surveillance and follow-up scheduling in this vulnerable population.