Relationship between Neutrophil-to-Lymphocyte Ratio and Pulse Wave Velocity in Young Patients with Systemic Lupus Erythematosus

Abstract

Background: The incidence of atherosclerosis-related myocardial infarction can be as much as 50-fold greater in young patients with systemic lupus erythematosus (SLE) than in age-matched controls. There are several explanations for this phenomenon, all of which result in a chronic state of low-grade inflammation. Recently, the neutrophil-to-lymphocyte ratio (NLR) has been proposed as a useful biomarker of inflammation. Pulse wave velocity (PWV) is a reliable indicator of vascular damage and atherosclerosis. There is a paucity of data concerning the relationship between NLR and atherosclerosis as measured by PWV in patients with SLE. This study aimed to verify whether there is a positive correlation between NLR and PWV and to explore factors that influence PWV in young SLE patients.

Methods: A total of 90 female patients with SLE were enrolled in this cross-sectional investigation. Traditional and nontraditional cardiovascular risk factors were assessed on the same day that brachial-ankle PWV (baPWV) was examined. The patients were divided into three groups according to their mean baPWV values: patients whose mean baPWV value was lower than the first tertile were placed in Group 1; patients whose mean baPWV value was between the first tertile and the second tertile were placed in Group 2; and patients whose mean baPWV value was higher than the second tertile were placed in Group 3. SPSS 20.0 was used to perform all statistical analyses in this study. Both univariate linear regression and multivariate regression models were utilized to analyze the association between NLR and arterial stiffness.

Results: Systolic blood pressure, diastolic blood pressure (DBP), and triglycerides were all significantly different among Groups 1, 2, and 3 (111.90 ± 12.85 mmHg vs. 114.60 ± 12.88 mmHg vs. 129.43 ± 16.21 mmHg, P < 0.001; 68.77 ± 8.63 mmHg vs. 71.87 ± 9.77 mmHg vs. 82.57 ± 14.89 mmHg, P < 0.001; and 1.44 [0.91-2.47] mmol/L vs. 0.98 [0.78-1.26] mmol/L vs. 2.20 [0.94-3.66] mmol/L, P = 0.030; respectively), as were creatinine (57.50 [52.00-69.00] μmol/L vs. 55.50 [49.00-64.00] μmol/L vs. 64.00 [56.00-86.00] μmol/L, P = 0.045) and blood urea nitrogen (4.27 [3.79-6.22] mmol/L vs. 4.16 [3.47-4.84] mmol/L vs. 5.88 [4.04-8.19] mmol/L, P = 0.011). NLRs were significantly different among Groups 1, 2, and 3 (2.16 [1.56-3.42] vs. 3.12 [1.91-4.19] vs. 5.29 [2.63-7.25], P = 0.001). NLR, together with DBP and the SLE disease activity index, independently predicts PWV.

Conclusions: This study demonstrated that there was a positive correlation between NLR and PWV. Moreover, we found that disease activity and DBP were also positively correlated with PWV.

Figure 1

Correlation of mean PWV and NLR in young systemic lupus erythematosus patients (n = 90; P = 0.022, R² = 0.058). PWV: Pulse wave velocity; NLR: Neutrophil-to-lymphocyte ratio.