C54-12 Pre-Discharge Red Cell Distribution Width (RDW) and One-year Mortality in Sepsis Survivors

Rationale Sepsis survivors remain at increased risk of mortality after hospital discharge, yet reliable long-term risk predictors are lacking. Persistent systemic inflammation after sepsis may disrupt bone marrow function and iron metabolism, impairing erythropoietin (EPO) signaling and reducing erythrocyte production, maturation, and survival, which leads to anisocytosis. Red cell distribution width (RDW), an inexpensive and routinely reported parameter, is an index of anisocytosis and may indicate persistent inflammatory and hematopoietic dysregulation at discharge, both associated with adverse outcomes. We evaluated whether pre-discharge RDW independently predicts 1-year mortality among adult sepsis survivors. Methods We conducted a retrospective cohort study using the MIMIC-IV database. Adults (≥18 years) meeting Sepsis-3 criteria with an ICU stay >24 hours were included; only the first admission was analyzed. Patients who died during the index hospitalization were excluded. Pre-discharge RDW was defined as the last value obtained within 72 hours before discharge. Values in the top and bottom 1% were removed to limit outliers. The primary outcome was all-cause mortality within one year of discharge. Cox regression models estimated hazard ratios (HRs) for RDW quartiles, adjusted for age, sex, weight, baseline creatinine, SOFA score, OASIS score, Charlson Index, hospital and ICU length of stay (LOS), early vasopressor use, renal replacement therapy, and transfusions during hospitalization. Model discrimination was evaluated with Harrell’s C-statistic, and restricted cubic splines assessed non-linear associations. Results Among 10,204 ICU sepsis survivors, 2,211 (21.7%) died within 1 year of discharge. The median(IQR) pre-discharge RDW was 14.7% (13.7-16.3). One-year mortality steadily increased across RDW quartiles: 8.6%, 14.8%, 23.6% and 38.9% (p < 0.005). Adjusted hazard ratios (HRs) for one year mortality remained strongly associated with higher pre-discharge RDW: Q1 (reference); Q2 HR 1.34 (95% CI 1.13-1.59); Q3 HR 2.00 (1.71-2.35); and Q4 HR 3.21 (2.74-3.75), p-trend <0.005. Patients in the highest RDW quartile had more comorbidities and longer LOS, while OASIS and SOFA scores were similar. Spline analyses showed a graded, near-linear association between RDW and one-year mortality, without a clear threshold. Adding pre-discharge RDW to a clinical model including all covariates used in the adjusted analysis significantly improved discrimination for one-year mortality (C-statistic 0.782 vs. 0.761). Conclusion Pre-discharge RDW was independently associated with 1-year mortality among ICU sepsis survivors. As a simple and routinely available parameter, RDW may help identify patients at higher risk after discharge; however, further studies are needed to clarify underlying mechanisms and evaluate its potential role in post-sepsis risk stratification. This abstract is funded by: None