Risk Factors And Association With Outcome For New-onset Cardiac Valve Calcification In Peritoneal Dialysis Patients

Objective : Patients with end-stage renal disease are susceptible to cardiac valve calcification(CVC) due to mineral metabolism disorders and other factors. The purpose of this study was to investigate the proportion, risk factors and the association with outcome for new-onset CVC in patients on maintenance peritoneal dialysis.Methods: 1. This study included patients who underwent PD catheter insertion from January 2006 to June 2013 in our Peritoneal Dialysis Center. The data collected included intact parathyroid hormone(i PTH), C-reactive protein(CRP), serum phosphorus(P),serum calcium, albumin(Alb), prealbumin(PA) and the use of five types of antihypertensive drugs, statins, active vitamin D3(VD3), and calcium tablets. Clinical data were collected on CVC status during echocardiography evaluations(twice) at an interval of more than six months. Uni- multivariate logistic regression was used identify the risk factors for the new-onset cardiac valve calcification.Statistical analysis was performed using SPSS for Windows, version 19.0(SPSS Inc.Chicago, IL, USA), and p<0.05 was considered statistical significance.2. The patients who undergoing peritoneal dialysis(PD) and regular follow-up in our dialysis center from January 1, 2006 to June 30, 2013 were selected for follow-up until June 30, 2015 to calculate the outcome. Demographic date, blood assayed, the cause of chronic renal disease, estimated glomerular filtration rate(e GFR), echocardiographic measurements at baseline and an interval of more than six months was recoded. The Kaplan-Meier was used to analysis the survival between calcification and without calcification. A Log-rank test was used to significance analysis. Calcification patients were matched to not-calcification according to propensity score. Using multivariate COX regression analysis to calculated the hazard ratio(HR).Statistical analysis was performed using SPSS for Windows, version 22.0(SPSS Inc.Chicago, IL, USA), and p<0.05 was considered statistical significance.Results: 1. In total, 194 patients with 100 men were included.(1) CVC was present in50 patients during placement of PD catheter. After an average PD duration of 20.9 ± 10.4months, CVC was detected in 97 patients. New-onset CVC was found in 62 patients.(2)Compared to the non-CVC group, the new-onset group had a more BMI, longer dialysis duration, a larger proportion of patients using statins, a higher proportion of patients with diabetes, higher serum P levels, and lower serum Alb levels; the differences were statistically significant.(3) No significant differences between the two groups with regard to age, gender, serum Ca, i PTH, CRP, PAB, ALB, TG, and TC levels; or the proportion of patients using antihypertensive drugs, Ca tablets, and active VD3 preparations.(4) The results of univariate regression analysis revealed that a history of diabetes; serum P, CRP,and Alb levels; BMI; dialysis duration; and use of statins were significantly associated with CVC.(5) Multivariate logistic regression analysis revealed that only serum P levels(p= 0.01, OR = 2.569), Alb levels(p = 0.04, OR = 0.935), dialysis duration(p = 0.03, OR =1.039), and CRP levels(p = 0.02, OR = 1.031) were associated with CVC.2. In end, 310 patients with 73 patients had valve calcification on baseline were included.(1) On baseline compared to the non-CVC group, the new-onset group had a greater age, shorter dialysis duration, a higher proportion of patients with diabetes, higher serum CRP levels, and lower serum creatinine and prealbumin levels; about the cause of chronic renal disease the proportion of diabetic nephropathy and hypertensive nephrosclerosis is higher, the proportion of chronic golmerulonephritis is lower. The differences were statistically significant.(2) After an average PD duration of40.2±25.5months, 87 patients was died. The average mortality of calcification is 50.7%,not-calcification is 20.7%.(3) Using Kaplan-Meier to calculate the 1-year, 3-year, and5-year survival rates of the patients in the not-calcification group were 97.25%, 91.2%, and87.75%, respectively, and these rates in the calcification group were 86.15%, 64.9%, and50%, respectively. The differences in the survival rates between the two groups were statistically significant difference(p<0.001).(4) Correction confounders were abjusted by multivariate COX regression analysis, we found the age, the cause of chronic renal disease,prealbumin levels are the independent risk factors that affect survival rate. But the survival rates between the two calcification and not-calcification were not different.(5) 128 patients were included in the subsampling after matched according to propensity score, with 73 patients had valve calcification. Compared to the baseline characteristics before matching,there are no difference in proportion of patients with diabetes and prealbumin levels,between the calcification and no-calcification groups. Meanwhile, the difference in age,serum creatinine and CRP levels is lower.(6) Using Kaplan-Meier(P=0.007) and multivariate COX regression analysis(P=0.034), the results reveal the valve calcification is associated with cumulative survival on maintenance peritoneal dialysis patients.(7) After an PD duration more than 6 months, new-onset CVC was detected in 68 patients. A layering research was going on based on whether present new-onset CVC. The results show the survival of not-calcification patients on baseline who have new-onset CVC during the peritoneal duration is lower.Conclusion: 1. Serum phosphorus, Alb, and CRP levels and dialysis duration are independent risk factors for new onset cardiac valve calcification.2. For the patients on maintenance peritoneal dialysis, the CVC on baseline and older age is the independent risk factor affecting survival rate.3. The new onset CVC during peritoneal dialysis duration is associated with the cumulative survival.