Prognostic implication of neutrophil-lymphocyte ratio (NLR) in myocarditis: results from a multicentre, multinational study

Abstract

Abstract Background Neutrophil–lymphocyte ratio (NLR) is an accessible inflammatory biomarker. Recently, baseline NLR has been shown to be independently associated with incident cardiovascular (CV) events and all-cause mortality. However, whether this applies to acute myocarditis (AM) has not been evaluated. The aim of the present study was to investigate the prognostic value of NLR in patients with AM. Methods All consecutive patients with a diagnosis of AM admitted to three tertiary referral cardiac centres in two countries between October 2006 and June 2020 were included in the study. Diagnosis was confirmed by either cardiac magnetic resonance or endomyocardial biopsy. The outcome measure was all-cause mortality. Patients were divided into two groups according to NLR value defined in previous studies (i.e., 2.5). Results A total of 287 patients with AM were included in the study. Baseline characteristics were comparable in both groups. Approximately two thirds of patients were males (n=194, 68%) with a mean age of 39±16 years. The main clinical presentation was predominantly infarct-like (n=215, 75%), followed by heart failure (HF) (n=46, 16%) and arrhythmic (n=26, 9%). Patients admitted with a HF presentation were more prevalent in the group with elevated NLR, while no difference was found in the other clinical presentations. For all patients, ECG features were comparable between groups. However, patients with elevated NLR presented with slightly higher LVEF (55±11% vs 50±13% respectively, p=0.003). Over a median follow-up of 54 months, higher NLR was associated with worse prognosis (Figure 1, p=0.02). Patients with high NLR have a 7-fold higher risk of adverse events during follow-up (Hazard Ratio 7.83, 95% confidence interval 1.02–59.89, p=0.047). Conclusions NLR is a promising and accessible inflammatory biomarker. In patients with AM, elevated NLR is associated with worse prognosis. Further research is advocated to confirm these data in larger populations. Funding Acknowledgement Type of funding sources: None.