The Relationship Between Neutrophil To Lymphocyte Ratio And The Loss Of Residual Renal Function In Peritoneal Dialysis Patients

BackgroundRetaining residual renal function(RRF)is of great significance to the overall health and well-being of patients undergoing peritoneal dialysis(PD).The reduction or loss of RRF will not only significantly aggravate complications such as anemia,protein-energy malnutrition,calcium and phosphorus disorders,and myocardial hypertrophy in PD patients.More importantly it is also an independent risk factor for cardiovascular death and all-cause death.Among the many factors that affect the decline of RRF,the microinflammatory state of PD patients is a research area that has received extensive attention in recent years.In a micro-inflammatory state,a large number of inflammatory mediators will appear in the body.These inflammatory mediators may damage kidney tissue by promoting the influx of monocytes and macrophages,the occurrence of oxidative stress,the proliferation of mesangial cells and endothelial extracellular matrix,and the attraction of profibrotic factors.The inflammatory response is a complex cascade involving a large number of inflammatory mediators,so the diagnosis of the inflammatory state mainly depends on detecting the level of inflammation markers.In recent years,the ratio of Neutrophils to Lymphocytes(NLR)has attracted more and more attention as a marker of inflammation.Many literatures have reported that NLR can be used to evaluate the severity of various inflammatory diseases and predict the adverse prognosis in clinical.For example,predicting the occurrence and development of related complications in type 2 diabetes,predicting the risk of death in acute myocardial infarction,predicting the risk of metastasis and death in a variety of malignant tumors,and so on.In PD patients,it was also reported that the baseline NLR of dialysis patients was negatively correlated with nutritional status,and positively correlated with erythropoietin resistance,vascular calcification,atherosclerosis,the incidence of cardiovascular events and mortality.However,little is known about the association between the baseline NLR and the loss of RRF in PD patients.ObjectivesThe purpose of this study was to investigate whether NLR is associated with the decline rate of RRF and the risk of RRF loss in PD patients.MethodsThis study is a single-center,retrospective,observational study.We reviewed the medical records of continuous ambulatory peritoneal dialysis(CAPD)patients who underwent PD tube placement surgery from Jan 1,2010 to Dec 31,2016 at ZhuJiang Hospital.All selected patients were followed up to December 31,2018,or reached the state of RRF loss,or switched to hemodialysis,or had a kidney transplant,or died or were lost to follow-up.We collected demographic,clinical and laboratory data from each patient at the time of the first peritoneal equilibration test(PET)after initiation of PD therapy and every 3-6 months thereafter.Demographic data included age,sex,body mass index(BMI),systolic(SBP)and diastolic(DBP).Clinical data included etiology of ESRD,comorbid conditions such as hypertension and diabetes,episodes of peritonitis,usage of ACEI/ARB drugs.Laboratory data included blood routine,renal function indicators,biochemical indicators,anemia indicators,and so on.The primary outcome of this study was:complete loss of RRF,defined as two consecutive 24-hour urine volumes<100mL.Data analysisPatients were divided to high and low NLR groups according to median value of their baseline NLR.Baseline characteristics and the decline rate of RRF over time were compared between two groups.Spearman's bivariate correlation analysis was used to analyze the correlation between the decline rate of RRF and other research factors.The Kaplan-Meier curve was used to compare the differences in the preservation rate of RRF between the two groups of CAPD patients.We used univariate and multiple COX regression models to analyze the independent predictive value of NLR levels for the loss of RRF.Statistical analysis was performed using SPSS software,version 20.0.Bilateral statistical standard p-value<0.05 was considered statistically significant.Results1.The RRF reduction rate was significantly greater in patients with high NLR(NLR>2.365)compared with those with low NLR(NLR?2.365)(p=0.003).2.Spearman's bivariate correlation analysis revealed a significant negative correlation between baseline serum NLR levels and the RRF reduction rates(r=-0.212,p=0.001).3.Kaplan-Meier curve indicated that the preservation rate of RRF in CAPD patients with low NLR group was significantly higher than that with high NLR group.(Log Rank=5.950,p=0.015);4.The COX regression models showed that high NLR levels have independent predictive value for the risk of loss of RRF in CAPD patients after adjustments for potential confounding factors.(HR=1.843,95%CI:1.237-2.746,p=0.003).ConclusionIn this study,our results showed that higher baseline serum NLR levels are significantly associated with a faster rate of RRF decline and an increased risk of RRF loss in PD patients.