Usefulness of Neutrophil-to-Lymphocyte Ratio (NLR) in predicting adverse outcomes in adult patients with heart failure : A systematic review and meta analysis

Background Inflammation plays a potential role in heart failure (HF) etiology and prognosis. Neutrophil-to-Lymphocyte ratio (NLR) is a simple, routinely available lab criteria. In this meta-analysis, we sought to investigate the role of NLR on HF outcomes which remains unexplored. Methods PubMed, Embase and Scopus were systematically screened to find studies through August 2022, reporting data on association of HF related outcomes [all-cause mortality (ACM), cardiovascular (CV) death, in-hospital, HF readmissions and composite events] and NLR. Random effects models and I2 statistics were used to estimate pooled odds of outcomes and heterogeneity. Leave one out sensitivity analysis was performed. Results A total of 11 studies (6 retrospective and 5 prospective, 4 studies from Asia and Europe each, 2 from the US and 1 multicenter study) including 12954 patients (mean age: 69 years, Males 57.2%) from 2011 to 2022 with an average follow up duration of 54.8 months were included. Elevated NLR was significantly associated with ACM (aOR 1.80, 95%CI 1.46-2.22, p<0.01, Table 1), HF readmissions (aOR 2.53, 95% CI 1.60-3.99), in-hospital mortality (aOR 3.26, 95% CI 1.76- 6.02), CV mortality (aOR 1.84, 95%CI 1.03-3.31) and composite CV outcome including heart transplant (OR 2.07, 95% CI 1.32-3.25), p<0.001. Conclusion Elevated NLR was significantly associated with worse outcomes in HF patients. The NLR test might potentially be useful in identifying high-risk HF patients and curtail worse outcomes.