Neutrophil-to-Lymphocyte Ratio and Fibroblast Growth Factor 21: Their Role in Early Cardiovascular Involvement in Rheumatoid Arthritis

<b>Introduction:</b> Rheumatoid arthritis (RA) is associated with increased cardiovascular morbidity and mortality. Left ventricular diastolic dysfunction (LVDD) represents an early sign of cardiac involvement in RA. <b>Objectives:</b> This study aimed to evaluate the incidence of LVDD and the association of the neutrophil-to-lymphocyte ratio (NLR) and circulating FGF21 levels with chosen LVDD echocardiographic parameters, as well as to assess their diagnostic utility for LVDD in a cohort of patients with RA. <b>Patients and Methods:</b> A total of 51 RA patients (46 females, 5 males; average age 48.8 ± 8.2 years; median disease duration of 12 years) were enrolled. NLR and serum FGF21 levels were analysed for association with echocardiographic parameters of LVDD using univariate regression models. The diagnostic performance of these markers was evaluated by receiver operating characteristic (ROC) analysis. <b>Results:</b> LVDD was diagnosed in 10 patients (19.6%). The NLR was associated negatively with E velocity (β = -4.99, <i>p</i> = 0.02), E/A ratio (β = -0.16, <i>p</i> = 0.004), lateral and medial e' velocities (β = -1.05, <i>p</i> = 0.038 and β = -0.97, <i>p</i> = 0.013, respectively), and positively with left atrial diameter (β = 2.08, <i>p</i> = 0.006). Serum FGF21 levels were negatively associated with the E/A ratio (β = -0.0005, <i>p</i> = 0.009) and lateral e' velocity (β = -0.003, <i>p</i> = 0.04). ROC analysis demonstrated a greater diagnostic value for NLR (Youden index 0.30, cut-off point 2.26, sensitivity 50%, specificity 80%, and area under curve [AUC] 0.58) compared to FGF21 (Youden index 0.30, cut-off value 852.85 pg/mL, 100% specificity, 30% sensitivity, and AUC 0.48). <b>Conclusions:</b> NLR and FGF21 are associated with the echocardiographic parameters of the left ventricular diastolic dysfunction prior to the fulfilment of LVDD diagnostic criteria. RA patients with elevated NLR and FGF21 serum levels should be considered for LVDD screening.