Neutrophil to lymphocyte ratio (NLR) prognostic effects on heart failure; a systematic review and meta-analysis

Abstract

Background Neutrophil to lymphocyte ratio (NLR), as a recent inflammatory index, has been reported to be a prognostic tool in different diseases. However, implication of this ratio in heart failure (HF) is less investigated. In this systematic review and meta-analysis, we aimed to assess the potential impact of NLR on HF clinical outcomes. Methods Relevant English published records in PubMed, Scopus, Embase, and Web of Science were screened up to July 2023. Articles reporting clinical outcomes (follow-up or in-hospital mortality, readmission, HF prediction, extended hospital stay length, pulmonary vascular resistance, atrial fibrillation, renal disease and functional capacity) in HF sufferers were collected for further analysis with addition of NLR difference stratified by death/survived and HF status. Results Thirty-six articles (n = 18231) were finally selected which reported NLR in HF sufferers (mean: 4.38, 95% confidence interval (CI): 4.02–4.73). We found 25 articles reported NLR and total mortality (either follow-up death (N = 19): 4.52 (95% CI: 4.03–5.01) or in-hospital death (N = 10): 5.33 (95% CI: 4.08–6.57)) with mean NLR of 4.74 (95% CI: 4.28–5.20). NLR was higher among deceased patients compared to survived ones (standard mean difference: 0.67 (95% CI: 0.48–0.87), P < 0.001)). NLR was found to be related with higher mortality risk (continuous variable: hazard ratio (HR): 1.12, 95% CI: 1.02–1.23, P = 0.013), categorical variable: HR: 1.77, 95% CI: 1.27–2.46, P = 0.001, T2 vs. T1: HR:1.56, 95%CI: 1.21–2.00, P = 0.001, T3 vs. T1: HR:2.49, 95%CI: 1.85–3.35, P < 0.001). Other aforementioned variables were not feasible to analyze due to presence of few studies. Conclusions NLR is a simple and acceptable prognostic tool for risk stratification and prioritizing high risk patients in clinical settings, especially in resource limited nations.

Targeting Key Inflammatory Mechanisms Underlying Heart Failure: A Comprehensive Review

“…Neutrophil-to-lymphocyte ratio (NLR) has been investigated as a recent inflammatory index and a prognostic tool in HF during the last few years. It is a simple prognostic tool for risk stratification and prioritizing high risk patients in clinical settings, especially in resource-limited nations [ 110 ]. In a recent meta-analysis [ 110 ], it was found that mean NLR in HF patients was 4.38 (95% CI: 4.02–4.73).…”

“…It is a simple prognostic tool for risk stratification and prioritizing high risk patients in clinical settings, especially in resource-limited nations [ 110 ]. In a recent meta-analysis [ 110 ], it was found that mean NLR in HF patients was 4.38 (95% CI: 4.02–4.73). Each unit increase in this biomarker has been associated with an increased mortality risk of 1.12 (95% CI: 1.02–1.23, p = 0.013) times, and this risk was higher among patients with higher NLR values than proposed cut-offs (HR: 1.77, 95% CI: 1.27–2.46, p = 0.001); being in a higher NLR tertile was associated with increased death likelihood (T2 vs. T1: HR: 1.56, 95% CI: 1.21–2.00, p = 0.001, T3 vs. T1: HR: 2.49, 95% CI: 1.85–3.35, p < 0.001) [ 110 ]; and NLR could be considered as a biomarker that mirrors the balance between acute and chronic inflammation and adaptive immunity, as well as a robust prognostic marker of disease severity and predictor of mortality in several diseases, including sepsis, pneumonia, COVID-19, cancer and cardiovascular diseases [ 111 ].…”