The Associations Of Trace Elements Imbalance With Hyperlipidemia And Hyperphosphatemia In Patients Undergoing Peritoneal Dialysis

Objectives: Imbalance of elements,especially trace elements,play vital roles in the development of chronic kidney disease with limited investigations.Our objective is to investigate the daily excretions and serum levels of trace elements in chronic kidney disease patients with continuous ambulatory peritoneal dialysis(CAPD).Besides,we also aim to explore the associations of trace elements with hyperlipidemia and hyperphosphatemia.Methods: This case-control study firstly included 61 CAPD patients between June 2013 and March 2014 and collected 24-hour urines and 24-hour dialysates.And we secondly included 87 CAPD patients between March 2016 and March 2017 and collected serums.Thirty-seven healthy subjects were included between June 2016 and March 2017 and the samples of serums and 24-hour urines were collected.We collected the demographic data of all study populations.Then,thepatients were divided into nonanuric group and anuric group by whether 24-hour urine volumes greater than 100 mL/d or not.According to serum total triglyceride(TG),they were also divided into normal triglyceride group(NT,TG < 1.72 mmol/L)and hypertriglyceridemia group(HT,TG ≥ 1.72 mmol/L).Besides,hyperphosphatemia was defined as serum phosphorous level greater than 1.78 mmol/L,and then patients were divided into hyperphosphatemia(HPA)and non-hyperphosphatemia group(NHPA).Various clinical biochemical variables were obtained from automatic biochemical analyzer.The concentrations of chromium,manganese,copper,zinc,selenium,molybdenum and arsenic in samples were determined using inductively coupled plasma mass spectrometer(ICP-MS).The total daily excretions of trace elements in CAPD patients in a dialysis day were evaluated by the sum of these elements amounts excreted by dialysate and urine.The reference values for serum levels of trace elements in Chinese population were taken as a reference.Besides,various statistical methods were applied to this study including Mann-Whitney U rank test,the Spearman rank correlation,multiple linear regression models and logistic regression models.Results: 1.Compared to healthy volunteers,total daily excretions of chromium,manganese,and copper in all CAPD patients were higher.Besides,daily excretions of zinc,selenium,and molybdenum in nonanuric patients were higher,while the excretion of arsenic in anuric patients was lower(P < 0.050).According to reference values,the proportions of CAPD patients with excessive serum chromium,molybdenum,arsenic,copper and manganese were 97.7%,98.5%,100%,13.79% and 14.94%,respectively.54.03%,22.99%,36.78% and 40.23% patients showed the low serum levels of zinc,selenium,copper and manganese,respectively.2.Serum levels of copper and arsenic in CAPD patients of HT group were significantly higher as compared to the NT group.According to the results of the Spearman rank correlations(r = 0.483,P < 0.050)and multiple linear regression models(standardized β = 0.272,P < 0.050),serum copper was positively associated with serum TG.3.Compared to patients in NHPA group,patients in HPA group showed higher serum arsenic levels.Moreover,a positive correlation of serum phosphorus was found with serum arsenic(r = 0.453,P < 0.001).The results of logistic regression analysis revealed that serum arsenic was still related to hyperphosphatemia after adjusting the potential confounding factors(OR,1.702;95%CI,1.052-2.755).Conclusions: Our results indicated that nonanuric CAPD patients might suffer from deficiency of zinc and Se,while anuric patients were at risk of arsenic accumulation.Besides,serum copper was positively correlated with TG.Moreover,serum arsenic was independently associated with hyperphosphatemia.At the same time,it suggested that the excess of copper and arsenic and the deficiency of zinc and selenium should be taken into consideration for CAPD patients in clinical treatments.