Elevated Neutrophil-to-Lymphocyte Ratio Predicts Prognosis in Acute Myocarditis.

Background: Neutrophil-to-lymphocyte ratio (NLR) is an easy-to-use inflammatory biomarker. Baseline NLR is independently associated with incident cardiovascular events and all-cause mortality. However, whether this applies to acute myocarditis (AM) has not been evaluated.
Objectives: The present study aimed to investigate the prognostic value of NLR in patients with AM.
Methods: A total of 1,150 consecutive patients with a diagnosis of AM admitted to 10 international tertiary referral cardiac centers were included in the study. The diagnosis was confirmed using cardiac magnetic resonance or endomyocardial biopsy. The primary outcome measure was a composite of all-cause mortality or heart transplantation. Patients were divided into 2 groups according to an NLR cutoff of 4 derived from spline regression analysis and 70:30 train-test split algorithm.
Results: Patients with an NLR <4 were younger and more likely to present with chest pain, and those with an NLR ≥4 were more likely to present with breathlessness and have other comorbidities. Over a median follow-up of 228 weeks, a NLR ≥4 was associated with a worse prognosis (P < 0.0001). After adjustment for prognostic variables, NLR emerged as an independent predictor of outcome (HR: 3.03 [95% CI: 1.30-7.04]; P = 0.010). Elevated NLR remained associated with worse outcomes among patients with preserved ejection fraction at baseline, who are conventionally considered to be at lower risk of adverse events (P < 0.0001).
Conclusions: In patients with AM, elevated NLR is associated with worse prognosis and may be valuable for stratifying patients, even those conventionally considered at low risk.
Competing Interests: Funding Support and Author Disclosures Dr Cannata is supported by the British Heart Foundation (FS/CRTF/21/24175). Dr Shah is supported by the British Heart Foundation (CH/1999001/11735). Dr Bromage is supported by a Medical Research Council Clinician Scientist Fellowship (MR/X001881/1) and the King’s BHF Centre of Research Excellence (RE/18/2/34213). Dr Tschöpe has received speaker fees and/or contributions to meetings from Abbott, Abiomed, AstraZeneca, Bayer, BMS, Boston Scientific, Impulse Dynamics, Novartis, Pfizer, MS, and Viofor, all outside of the work included in this study. Dr Gräni has received research funding from the Swiss National Science Foundation and Innosuisse, the Center for Artificial Intelligence in Medicine Research Project Fund University Bern, Novartis science foundation, and the GAMBIT foundation, outside of the submitted work. Dr Ameri has received speaker and/or consultancy fees from AstraZeneca, Boehringer Ingelheim, Bayer, Daiichi Sankyo, Janssen, Merck Sharp & Dohme, and Gossamer Bio, all outside the submitted work. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
(Copyright © 2025 The Authors. Published by Elsevier Inc. All rights reserved.)