Discharge Neutrophil-to-Lymphocyte Ratio and Its Trajectory as Predictors of 30-Day Outcomes in Acute Heart Failure

Aims To evaluate whether discharge neutrophil-to-lymphocyte ratio (NLR) and its in-hospital trajectory predict 30-day outcomes after acute decompensated heart failure (ADHF) hospitalization, and to compare discharge NLR with admission NLR and with serial NLR measurement. Methods Retrospective cohort of 6,784 ADHF discharges (2007–2017; median age 78 [IQR 69–85] years; 48.8% women). Patients were classified by discharge NLR (<5 vs ≥5) and by NLR trajectory (low→low, low→high, high→low, high→high). Primary endpoints were 30-day all-cause readmission and 30-day all-cause mortality. Multivariable Cox models adjusted for age, sex, anemia, chronic kidney disease, diabetes, ischemic heart disease, atrial fibrillation, peripheral vascular disease, and COPD. Discrimination was assessed using AUCs from adjusted logistic models. Results High discharge NLR (≥5) was present in 2,258/6,784 (33.3%). Event rates were higher with high vs low discharge NLR for readmission (25.5% vs 19.7%, p<0.001) and mortality (7.8% vs 2.8%, p<0.001). High discharge NLR was independently associated with readmission (HR 1.21, 95% CI 1.05–1.40, p=0.007) and mortality (HR 1.92, 95% CI 1.46–2.53, p<0.001). Trajectory further stratified risk: high→high had the greatest risk (readmission HR 1.42, 95% CI 1.25–1.62, p<0.001; mortality HR 3.42, 95% CI 2.53–4.62, p<0.001); low→high was also high-risk (readmission HR 1.46, 95% CI 1.20–1.77, p<0.001; mortality HR 3.05, 95% CI 2.00–4.65, p<0.001). High→low showed reduced but residual risk vs low→low (readmission HR 1.07, 95% CI 0.93–1.23, p=0.321; mortality HR 1.52, 95% CI 1.06–2.16, p=0.021). Discharge NLR outperformed admission NLR (mortality AUC 0.731 vs 0.705; readmission AUC 0.573 vs 0.564). Serial NLR added minimal discrimination beyond discharge NLR alone (mortality AUC 0.736 vs 0.734; readmission AUC 0.571 for both). Conclusions Discharge NLR is an independently prognostic, routinely available biomarker for 30-day readmission and mortality after ADHF. Persistently elevated or rising NLR identifies patients at highest short-term risk, while normalization attenuates but does not eliminate risk. A single discharge measurement performs comparably to serial assessment, supporting practical integration of discharge NLR into risk-stratified follow-up, including in resource-limited settings.