The Relationship Between Fibrinogen To Albumin Ration And Prognosis In Patients On Peritoneal Dialysis

BackgroundCardiovascular disease(CVD)is the primary cause of death in dialysis patients.Many studies have demonstrated that microinflammation is prevalent in peritoneal dialysis(PD)patients and it is an important factor leading to the occurrence and development of cardiovascular disease.The fibrinogen to albumin ratio(FAR),calculated by dividing the plasma fibrinogen level by the serum albumin level,is a new clinical inflammatory marker proposed in recent years,which has been shown to be positively correlated with microinflammation in many studies.Compared with the traditional microinflammation indexes,such as CRP,IL-6 and TNF-α,the FAR has the advantages of convenience,cheapness and easy access.Recently,several studies have reported that the FAR has a good prognostic value in inflammatory related diseases,such as,cardiovascular disease,tumor and ankylosing spondylitis.However,no research has investigated the prognostic value of the FAR in ESRD patients on PD.The purpose of this study was designed to retrospectively analyze the FAR value in predicting all-cause and CVD mortality in ESRD patients on PD.MethodsThis was a retrospective observational study.This study enrolled ESRD patients who underwent catheterization for peritoneal dialysis and initiated PD treatment in Zhujiang Hospital of Southern Medical University between January 1,2011 to December 31,2017.This study protocol was approved by the Southern Medical University Research Ethics CommitteeThe inclusion criteria were as follows:(1)the age was 18 years and above;(2)the peritoneal dialysis time was not less than 3 months;(3)the patients were generally in good condition and stable mental state.The exclusion criteria were as follows:(1)patients transferred from long-term hemodialysis(HD)or renal transplantation;(2)patients with recent acute infection;(3)patients with severe liver dysfunction;(4)patients with active rheumatic disease,blood system diseases or malignant tumor;(5)patients with consuming immunosuppressor medicine;(6)pregnant women;(7)patients with insufficient data of demographic information and clinical biochemical indicators.The primary outcome of this study was all-cause and CVD mortality.All of the patients were followed until death,or cessation of PD(transfer to long-term hemodialysis,kidney transplantation or lost to follow up),or June 30,2019Baseline demographic and clinical data were obtained at the time of enrollment.These factors included sex,age,blood pressure,body mass index(BMI),cause of ESRD,history of CVD,hypertension and diabetes,and laboratory characteristics included neutrophil to lymphocyte ratio(NLR),platelet to lymphocyte ratio(PLR),serum high sensitive C-reactive protein(hs-CRP),leucocyte count,plasma fibrinogen,serum albumin,hemoglobin,serum creatinine,serum urea nitrogen,total cholesterol,triglycerides,serum calcium,serum phosphorus,serum intact parathormone(iPTH)and serum uric acid.Baseline dialysis characteristics were obtained at the time of the first 1-3 months of PD,which included weekly total Kt/V urea(total Kt/V).The median FAR was 0.12,and patients were divided into two groups(low FAR group:FAR<0.12,n=250,and high FAR group:FAR>0.12,n=312)according to the median FAR.Differences between baseline characteristics of the two groups were observed and compared using Student’s t-test for normally distributed variables or using the Mann-Whitney U-test for variables not normally distributed.Categorical variables between groups were compared using the Chi-square test.Spearman’s bivariate correlation analysis was conducted to assess the relationship between FAR and inflammation indicators.Survival curves were estimated using the Kaplan-Meier method and compared using the log-rank test.Cox proportional hazard models were performed to estimate the risk factors for mortality.The eligible covariates used in the multivariate regression analyses demonstrated a significant association with mortality in univariate analysis(p<0.05)or for the importance of clinical concern.All the above tests were bilateral tests,p values less than 0.05 were considered statistically significant.Statistical analyses were performed using SPSS for Windows version 20.0(SPSS Inc).Results1.A total of 562 eligible incident PD patients were included in our study.Compared with patients in the low FAR group,those in the high FAR group were older(p<0.001),consisted of a higher proportion of males(p<0.001)and had a higher rate of diabetes mellitus(p<0.001).Besides,The high FAR group also had significantly lower level of haemoglobin(p<0.001),higher level of cholesterol(p<0.001)and higher level of triglycerides(p=0.007).More importantly,compared with patients in the low FAR group,the inflammatory markers,such as,NLR(p<0.001),PLR(p=0.004),hs-CRP level(p<0.001),and leucocyte count(p<0.001)were significantly higher in the high FAR group.2.Spearman correlation analysis showed that FAR was positively correlated with the other inflammatory indexes,such as NLR,PLR,hs-CRP,leukocyte count and plasma fibrinogen.while it was negatively correlated with serum albumin.3.The median follow-up period of this study was 35.2 months.Kaplan-Meier analyses indicated that the cumulative survival rate of patients with a high FAR(65.6%)was significantly lower than that of patients with a low FAR(87.5%)(log-rank=18,56,p<0.001),Similarly,the cardiovascular cumulative survival rates were also significantly lower in patients with a high FAR(74.8%)than in those with a low FAR(91.8%)(log-rank=14.81,p<0.001)4.Univariate and fully adjusted model of multivariate Cox regression analysis showed that a high FAR was associated with all-cause mortality(HR 1.80,95%CI 1.03-3.14,p=0.038)and CVD mortality(HR 2.31,95%CI 1.17-4.59,p=0.016)in ESRD patients on PD.5.The predictive power of the FAR and other inflammatory indexes was compared by the AUC of ROC curve analysis.The AUC values of FAR and other inflammatory indexes in terms of all-cause and CVD mortality showed that compared with NLR,PLR,leukocyte count,fibrinogen and albumin,the FAR showed a better distinguishing power for predicting all-cause and CVD mortality in PD patients.ConclusionHigh FAR is an independent risk factor for all-cause and CVD mortality in ESRD patients on PD.Compared with NLR,PLR,leukocyte count,fibrinogen and albumin,FAR showed a better distinguishing power for predicting all cause and CVD mortality in PD patients.