#2524 Pre-dialysis bile acids level and peritoneal dialysis patient outcome

Abstract Background and Aims The role of bile acids in regulating glucose and lipid metabolism, as well as their influence on the development of gut microbiota, has been well-established. Despite obvious abnormality of glucose metabolism and gut microbiota in PD patients, the relationship between bile acid levels and the risk of all-cause mortality in PD remains poorly understood. Therefore, this study aims to explore how pre-dialysis bile acid levels, in conjunction with various clinical factors and demographic characteristics, may impact the risk of all-cause mortality in PD patients. Method A single-center, retrospective cohort study was conducted on patients who underwent PD catheter placement at Peking University Third Hospital between July, 2010 and April 12, 2024, and followed up until September 25, 2024. Pre-dialysis bile acid level just before PD catheter placement were collected. The relationship between pre-dialysis bile acid levels and all-cause mortality risk was analyzed. The primary endpoint was all-cause mortality risk. Results A total of 532 PD patients were included and the mean pre-dialysis bile acid level was 3.03 µmol/L [IQR: 1.4–3.5]. The RCS-based BAs cutoff value was 2.2 µmol/L. Bile acid levels were negatively correlated with triglycerides (r = −0.0939, P = 0.031), total cholesterol (r = −0.1290, P = 0.003), LDL-c (r = −0.138, P = 0.001), parathyroid hormone (r = −0.0907, P = 0.035), and serum phosphorus (r = −0.120, P = 0.005), while they were positively correlated with direct bilirubin (r = 0.268, P < 0.001), HDL-c (r = 0.144, P < 0.001), and total bilirubin (r = 0.177, P < 0.001). During an average follow-up of 3.65 years (IQR: [1.34, 5.26]), 212 of 532 patients died. Compared with the low bile acid group (<2.2 µmol/L), the high bile acid group had a significantly higher risk of all-cause mortality (HR 1.67, 95% CI 1.288–2.230, P < 0.001) (Fig. 1). The risk of cardiovascular events (HR 1.431, 95% CI 1.099–1.864, P = 0.0075) and cerebrovascular events (HR 1.716, 95% CI 1.083–2.717, P = 0.020)was significantly higher in the high bile acid group compared to the low bile acid group. Cox regression analysis revealed that pre-dialysis bile acid levels (HR 1.045, 95% CI 1.003–1.092, P = 0.035) remain to be independent risk factor for mortality risk by adjudging for age, gender, BMI blood glucose, serum calcium, hemoglobin, serum albumin, serum PTH, total bilirubin, and comorbidities in Cox regression models (HR 1.396, 95% 1.049–1.859, P = 0.022). Conclusion In PD patients, elevated pre-dialysis bile acid levels were identified as an independent risk factor for all-cause mortality, as well as for cardiovascular and cerebrovascular events after PD initiation.