Association Of 24hours Urine Volume And Cardiovascular Events In Peritoneal Dialysis Patients

Background and Objective: Peritoneal dialysis(PD) was introduced in 1976 and afterwards it has become a treatment modality for end stage renal disease(ESRD). As the technique of peritoneal dialysis has improved rapidly, patients’ survival and quality of lives tend to better. But volume overload is still a common problem in peritoneal dialysis patients, which can have influence on the life quality of PD patients. It has been reported that fluid statue is associated with 24 hours urine volume. In addition, volume overload is an important risk factor for cardiovascular events, which is a major cause of death in dialysis patients, resulting to the increasing mortality rate in patients with PD as well as prognosis. Untill now, the relationship of24 hours urine volume and cardiovascular events has not been fully understood. In order to effectively reduce the risk of cardiovascular disease and improve the outcome of PD patients, we undertake the study of association of 24 hours urine volume and cardiovascular events with patient survival in continuous ambulatory peritoneal dialysis patients.Methods: 135 ESRD patients undergoing peritoneal dialysis for at least 6 months were enrolled during January 2012 to December 2014 in the Second Hospital of Tianjin Medical University peritoneal dialysis centre. All patients were divided into high 24 hours urine volume group and low 24 hours urine volume group according to a basic urine volume of 500 ml. Clinical characters were recorded, such as age,gender, primary disease, total serum protein, serum albumin, serum urea nitrogen,serum creatinine, hemoglobin, platelets, electrolytes, calcium, phosphorus,β2-microglobulin, BNP. Volume overload was determined by bioelectrical impedance analysis.Caridac output was also evaluated.Data are expressed as mean 土 SEM.Statistical analysis involved independent Student t test for comparing 2 groups and one-way ANOVA for multiple comparisons. Kanplan Meier analysis was used to analize the survival of patients. Multivariate Cox regression analysis was used to identify the risk factors. P<0.05 was considered statistically significant.Results:(1)There were 66 patients in group with urine volume above 500 ml and 69 patients in group with urine volume below 500 ml.The level of serumβ2-microglobulin, BNP, ECW and E/I ration were higher in low urine volume group than those in high uine volume group with P<0.05. Meanwhile, the level of ICW, CO and CI was higher in high urine volume group than those in low urine volume group with p-value<0.05. Furthermore, the prevalence of hypertension was higher in low urine volume group(P<0.05).(2)The incidence of caridovacular events was higher in low residual urine vol.ume group than that in high 24 hours urine volume group( ? 2=32.639, P<0.01)(3) During follow up period, 34 patients died,while 9patients died in high 24 hours urine volume group and 24 patients died in low residual uine volume group. The mortality rate in low residual uine volume group was higher than that in high 24 hours urine volume group( ? 2=8.167, P<0.01).(4) There was lower survival rate in the lower 24 hours urine volume group compared with that in high 24 hours urine volume group(?2=66.864,P<0.01). Similar trend was also found in cardiac event free survival rate(?2=15.417, P<0.01).(5)Furthermore, serum calcium,phosphate, BNP, β2-microglobulin,ECW and hypertension were the independent risk factors of mortality for continuous ambulatory peritoneal dialysis by Cox regression model.Conclusion: The incidence of cardiovascular event tends to be more frequent as the24 hours urine volume declines in peritoneal dialysis patients.Meanwhile, the middle molecular clearance was also reduced. As a result, blood pressure increased due to fluid overload, which indicate that protection of 24 hours urine volume is very important to reduce the incidence rate of cardiovascular event. Furthermore, control of metabolism of calcium and phosphate is helpful to improve the survival of peritoneal dialysis patients despite management of blood pressure, cardiofunction as well as volume input.