The ratio of neutrophils and lymphocytes as a marker of pulmonary hypertension in patients with respiratory diseases

Pulmonary hypertension (PH) is a common complication in patients with respiratory disease, aggravating clinical symptoms and significantly impacting prognosis. Chronic hypoxemia is considered the primary and best-studied cause of PH in this patient population. Recent studies have explored the role of inflammation in the pathogenesis of this vasculopathy. This article evaluates the potential clinical significance of the neutrophil-to-lymphocyte (Nf/Lf) ratio as a marker of systemic inflammation in patients with respiratory disease. The aim of this study was to determine the role of the Nf/Lf ratio in the diagnosis of pulmonary hypertension associated with respiratory diseases. Methods. This observational, single-center, cross-sectional study included 90 patients with various respiratory diseases, 69 of whom were diagnosed with PH. Patients were divided into two subgroups based on the presence of PH. A comprehensive examination was conducted in both groups, including: laboratory diagnostics, non-invasive hemodynamic assessment of pulmonary hypertension, a comprehensive study of pulmonary function, and multispiral computed tomography of the chest organs. Results. The obtained results demonstrated that the Nf/Lf ratio is statistically significantly higher and the absolute count of peripheral blood lymphocytes is statistically significantly lower in patients with PH. A univariate logistic regression analysis of potential predictors of PH showed that the absolute lymphocyte count and the Nf/Lf ratio in peripheral blood, as well as the partial oxygen tension in arterial blood (PaO₂) were associated with PH. In multivariate logistic regression analysis, the Nf/Lf ratio was identified as a statistically significant predictor of PH; an increase in the Nf/Lf ratio by 1 increases the chances of having PH by 2.4 times. ROC analysis determined the diagnostic significance of PaO₂ and the NF/Lf ratio for predicting PH: The AUC was 0.635 (95% confidence interval (CI) 0.506 – 0.765; p = 0.062) for PaO₂ and 0.726 (95% CI 0.612 – 0.841; p = 0.002) for the Nf/Lf ratio. The sensitivity and specificity for the presence of PH were 54.4% and 90.5%, respectively, with an Nf/Lf ratio ≥ 2.2. Conclusion. The Nf/Lf ratio can be considered an additional marker of PH in patients with respiratory pathology.

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