Neutrophil-to-lymphocyte ratio and C-reactive protein in patients admitted with Acute Dyspnoea suspected of acute heart failure

Background: Inflammation contributes to adverse outcomes among patients with acute dyspnoea. This study evaluates the prognostic relevance of Neutrophil-to-lymphocyte ratio (NLR) and C-reactive protein (CRP) in patients presenting to the emergency department (ED) with acute dyspnoea, including those with acute heart failure (AHF). Methods: This observational study included patients with acute dyspnoea. Diagnoses of AHF and non-AHF were adjudicated by cardiologist. NLR and CRP were measured at admission. Cutoff were determined using Receiver Operating Characteristic curves and Youden's index. The primary endpoint was all-cause mortality. Patients were followed for four years, and cox regression models assessed associations in the overall cohort and within subgroups. Results: We included 239 patients: 60 (25 %) with AHF and 179 (75 %) with non-AHF. NLR cutoff was 4.5, and CRP cutoff was 21.3 mg/L. During follow-up, 98 patients (41 %) died. NLR >4.5 was associated with mortality (HR: 2.7, 95 % CI: 1.7–4.2, p < 0.001). In subgroup analysis, NLR >4.5 remained associated with mortality in both AHF (HR 3.3, 95 % CI 1.34–8.2, p = 0.009) and non-AHF (HR 2.4, 95 % CI 1.4–4.2, p = 0.002). CRP >21.3 mg/L was associated with mortality (HR: 1.7, 95 % CI: 1.2–2.6, p = 0.007). In subgroup analysis, CRP >21.3 mg/L was associated with mortality in patients with AHF (HR: 2.7, 95 % CI: 1.3–5.7, p = 0.009), but not in non-AHF. Conclusion: NLR was associated with all-cause mortality in patients with acute dyspnoea across both cardiac and non-cardiac presentations. CRP was associated with all-cause mortality in patients with AHF.