Neutrophil-lymphocyte ratio is associated with arterial stiffness in patients with peritoneal dialysis

BACKGROUND: Patients with peritoneal dialysis are in the persistent inflammation state and have elevated arterial stiffness. Neutrophil-lymphocyte ratio(NLR) is a new inflammatory marker in renal and cardiac disorders. Brachial-ankle pulse wave velocity (baPWV) is a non-invasive measurement, which is widely used as a surrogate marker of arterial stiffness. However, there is little evidence to show an association between NLR and baPWV in patients with peritoneal dialysis. The aim of this cross-section study was to investigate the relationship between NLR and arterial stiffness measured by baPWV in patients with peritoneal dialysis. METHODS: In this cross-section study, 101 patients with peritoneal dialysis were enrolled from January 2014 to June 2015. According to average baPWV level (1847.54 cm/s), the patients were categorized into two groups, low group and high group. baPWV, which reflects arterial stiffness, was calculated using the single-point method. Clinical data were collected in details. NLR was calculated using complete blood count. Associations between NLR and baPWV were assessed using Pearson's correlation and linear regression analysis. RESULTS: The NLR was significantly lower in the low baPWV group than in the high baPWV group (p = 0.03). There were positive correlations between baPWV and neutrophil count (r = 0.24, p = 0.01) and NRL(r = 0.43, P < 0.01), and there was a negative correlation between baPWV and lymphocyte count (r = -0.23, p = 0.01). In addition, albumin, phosphorous and intact parathyroid hormone showed negative correlations with baPWV (r = -0.32, p < 0.01; r = -0.28, p < 0.01; r = -0.25, p = 0.01, respectively). Age and hsCRP showed positive correlations with baPWV (r = 0.47, p < 0.01; r = 0.25, p = 0.01). In multivariate analysis, NLR independently correlated with baPWV in patients with peritoneal dialysis (β = 0.33, p < 0.01), even after adjustment for various confounders. CONCLUSION: Our study suggests that NLR was an independently associated with arterial stiffness in patients with peritoneal dialysis. However, further prospective studies are needed to confirm cause-and-effect relationship between NLR and baPWV, and to investigate whether anti-inflammatory treatment could improve arterial stiffness in patients with peritoneal dialysis.