Serum lipoprotein(a) and risk of mortality in patients on peritoneal dialysis

Serum fibroblast growth factor 23 concentration and the risk of mortality in patients undergoing peritoneal dialysis

BACKGROUND

Fibroblast growth factor 23 (FGF23) is a phosphate-regulating hormone that is secreted in large amounts early in chronic kidney disease. In this cohort, we aimed to investigate the association between serum FGF23 concentration and mortality in patients undergoing peritoneal dialysis (PD).

METHODS

Serum FGF23 level was determined by enzyme-linked immunosorbent assay (ELISA) in a large 15-year prospective cohort study of PD patients with stored serum samples at baseline. Kaplan-Meier survival curves and Cox proportional hazards models were performed to characterise the relationship of FGF23 with mortality.

RESULTS

A total of 737 incident PD patients were analysed. The baseline median FGF23 concentration was 683.2 (518.5-896.2) pg/mL. Age, serum phosphorus, high-density lipoprotein cholesterol and high-sensitivity C-reactive protein were independently correlated with serum FGF23 concentration. During a median follow-up of 66.7 (41.1-95.4) months, 171 of the 737 participants (23.2%) died, including 84 (49.1%) cardiovascular disease-related and 50 (29.2%) infection-related deaths. Multivariable Cox regression analysis showed that the adjusted hazard ratios of the highest tertile of serum FGF23 compared with those in the lowest tertile were 1.36 (95% confidence interval (CI): 0.89-2.07; p = 0.154), 0.75 (95% CI: 0.40-1.38; p = 0.353) and 2.66 (95% CI: 1.15-6.15; p = 0.022) for all-cause, cardiovascular disease-related and infection-related mortality, respectively.

CONCLUSION

High serum FGF23 concentration is associated with a higher risk of infection-related death for incident PD patients.

Serum Hepcidin-25 and Risk of Mortality in Patients on Peritoneal Dialysis

Background: Increased serum hepcidin-25 level is associated with excess mortality in hemodialysis patients. However, there is a dearth of published information about its predictive effect for survival in patients on peritoneal dialysis (PD). The purpose of this study is to evaluate the association of serum hepcidin-25 with the risk of mortality in PD patients. Methods: Serum hepcidin-25 level was measured using an enzyme-linked immunosorbent assay in a prospective cohort study of PD patients with stored serum samples at baseline. Multivariate linear regression model was used to determine clinical characteristics associated with serum hepcidin-25 concentration. We evaluated the relationship between serum hepcidin-25 and all-cause mortality using a Cox proportional hazards model and the relationship between hepcidin-25 and cardiovascular (CV) and infection-related deaths using competing-risks regression models. Results: In total, 513 PD patients were included in this study. The median serum hepcidin-25 level was 40.9 (17.9-85.9) ng/mL. Body mass index and serum ferritin were positively correlated with serum hepcidin-25 levels. During a median follow-up period of 64.1 months, 122 (24%) patients died, including 61 (50%) CV deaths and 32 (26%) infection-related deaths. In multivariable analysis, patients with the highest tertile of serum hepcidin-25 had a greater risk of all-cause [adjusted hazard ratio (aHR) 1.85, 95% confidence interval (95%CI), 1.14 to 3.00, P = 0.013] and infection-related mortality (adjusted subdistribution hazard ratio [aSHR], 2.61; 95%CI, 1.01 to 6.76, P = 0.049) when compared with those in the second tertile. However, no significant relationship was observed between serum hepcidin-25 and CV mortality. Conclusions: Higher baseline serum hepcidin-25 level was associated with increased risk for all-cause and infection-related mortality in PD patients.

Abnormal iron status is associated with an increased risk of mortality in patients on peritoneal dialysis

BACKGROUND AND AIMS

Iron deficiency is prevalent, but there is limited data about the relationship between iron status and poor outcomes in chronic kidney disease patients undergoing peritoneal dialysis (PD). We aimed to investigate the association between iron status and mortality in PD patients.

METHODS AND RESULTS

This retrospective study was conducted on incident PD patients from January 2006 to December 2016 and followed up until December 2018. Patients were categorized into four groups according to baseline serum transferrin saturation (percent) and ferritin levels (ng/ml): reference (20-30%, 100-500 ng/ml), absolute iron deficiency (<20%, <100 ng/ml), function iron deficiency (FID) (<20%, >100 ng/ml), and high iron (>30%, >500 ng/ml). Among the 1173 patients, 77.5% had iron deficiency. During a median follow-up period of 43.7 months, compared with the reference group, the FID group was associated with increased risk for all-cause [adjusted hazard ratio (aHR) 1.87, 95% confidence interval (95% CI) 1.05-3.31, P = 0.032], but not cardiovascular (CV) mortality. Additionally, the high iron group had a more than four-fold increased risk of both all-cause and CV mortality [aHR 4.32 (95% CI 1.90-9.81), P < 0.001; aHR 4.41 (95% CI 1.47-13.27), P = 0.008; respectively].

CONCLUSION

FID and high iron predict worse prognosis of patients on PD.

The Effects of Hemodialysis and Peritoneal Dialysis on the Gut Microbiota of End-Stage Renal Disease Patients, and the Relationship Between Gut Microbiota and Patient Prognoses

Gut microbiota alterations occur in end-stage renal disease (ESRD) patients with or without dialysis. However, it remains unclear whether changes in gut microbiota of dialysis ESRD patients result from dialysis or ESRD, or both. Similarly, there is a dearth of information on the relationship between gut microbiota and ESRD prognoses. We collected fecal samples and tracked clinical outcomes from 73 ESRD patients, including 33 pre-dialysis ESRD patients, 19 peritoneal dialysis (PD) patients, and 21 hemodialysis (HD) patients. 16S rRNA sequencing and bioinformatics tools were used to analyze the gut microbiota of ESRD patients and healthy controls. Gut microbiota diversity was different before and after dialysis. Bacteroidetes were significantly deceased in HD patients. Twelve bacterial genera exhibited statistically significant differences, due to dialysis (all P < 0.05, FDR corrected). HD reversed abnormal changes in Oscillospira and SMB53 in pre-dialysis patients. Functional predictions of microbial communities showed that PD and HD altered signal transduction and metabolic pathways in ESRD patients. Furthermore, Bacteroides and Phascolarctobacterium were associated with cardiovascular mortality. Dorea, Clostridium, and SMB53 were related to peritonitis in PD patients. This study not only demonstrated differences in gut microbiota between pre-dialysis and dialysis ESRD patients, but also firstly proposed gut bacteria may exert an impact on patient prognosis.