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.