| Objective:High serum ferritin has been reported associated with the occurrence of infection in hemodialysis(HD)patients.However,the relationship between ferritin and peritoneal dialysis-related peritonitis in patients undergoing continuous ambulatory peritoneal dialysis(CAPD)remains unclear.The aim of this study was to examine whether a higher serum ferritin level at baseline predicts peritonitis.Methods:End-stage renal disease(ESRD)patients being treated with CAPD at Zhujiang Hospital of Southern Medical University and Jiangmen Central Hospital from January 1,2010 to June 30,2015 with follow-up until June 30,2016 were studied.The exclusion criteria for peritoneal dialysis patients were less than 18 years of age,PD treatment less than 90 days,loss to follow-up,experiencing active infections within 90 days after initiation of PD therapy,history of malignant tumor or chronic hepatitis.Patients were categorized into 2 groups according to their serum ferritin levels:high-ferritin group with levels no less than 500 ng/mL and low-ferritin group with levels below 500 ng/mL.Data obtained at the time of PD initiation included demographic details,etiology of end-stage renal disease(ESRD).Baseline biochemical data,a standard peritoneal equilibration test(PET),urea clearance index(weekly Kt/V)and residual glomerular filtration rate(rGFR)was evaluated in the first 3 months of PD therapy.For each patient the baseline biochemical data was defined as the average of all repeated measures done during the first 3 months.The treatment for anemia within 90 days after initiation of PD therapy were also recorded.During the follow-up period,we recorded all cases of peritonitis,including the date,organisms and the date patients dropped out from PD.Baseline data,peritonitis rates were compared between high-ferritin group and low-ferritin group.The correlation between baseline serum ferritin and the risk for peritonitis was determined by means of Kaplan-Meier analysis and Cox regression model.A two-tailed p-value<0.05 was defined statistically significant.Statistical analysis was performed by means of SPSS software,version 19.0.Results:594 patients were eligible for the study,including 117(20%)patients with ferritin higher than 500 ng/mL and 477(80%)patients lower than 500 ng/mL.The median value of ferritin was 204 ng/mL.The patients in high-ferritin group had significantly higher concentration of white blood cells(P = 0.023)and serum iron(P<0.001),while lower concentration of hemoglobin(P = 0.003)and total cholesterol(P = 0.001).Among the 594 patients,413(69.5%)patients had no peritonitis,while the remaining 181(30.5%)patients presented total 291 episodes of peritonitis during a cumulative follow-up period of 19577 patient-months,including 74 episodes in the high-ferritin group and 217 episodes in the low-ferritin group.The high-ferritin group experienced a higher peritonitis rate than the low-ferritin group(0.23 episodes per patient months vs 0.17 episodes per patient months,P = 0.016).Kaplan-Meier analysis showed that the cumulative peritonitis-free survival in high-ferritin group and low-ferritin group was 76.6%vs 88.6%,70.5%vs 77.9%,59.3%vs 70.2%,55.0%vs 63.1%,46.9%vs 57.0%for year 1 to 5,respectively.The cumulative peritonitis-free survival was significantly lower in the high-ferritin group patients as compared to other patients(Log-rank = 5.930,P = 0.015).Multivariate analysis demonstrated that high ferritin level and hypoalbuminemia were independently associated with increased risk for the first episode of peritonitis,with a hazard ratio of 1.503(95%CI = 1.076 to 2.099,P = 0.017)and 1.535(95%CI = 1.126 to 2.092,P =0.007),respectively.Conclusions:An elevated ferritin level at baseline was associated with the increased risk of peritoneal dialysis-related peritonitis.Hypoalbuminemia was also an independent risk factor for peritonitis. |
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