MON-784 Prognostic Implications of Serum Parathyroid Hormone and Calcium-Phosphorus Product in Peritoneal Dialysis: A Peritoneal Dialysis Outcomes and Practice Patterns Study (PDOPPS) Analysis

Abstract Disclosure: W. Oh: None. J. Park: None. Background: Chronic kidney disease-mineral and bone disorder (CKD-MBD) and renal osteodystrophy have been associated with mortality in peritoneal dialysis (PD) patients. PD patients with elevated parathyroid hormone (PTH), hyperphosphatemia and hypercalcemia especially face a risk of cardiovascular mortality due to vascular calcification and calciphylaxis. This correlation has not been extensively investigated in PD patients. Methods: The Peritoneal Dialysis Outcomes and Practice Patterns Study (PDOPPS) is a prospective cohort study, enrolling patients aged ≥18 years, designed to identify modifiable clinical practices associated with improved PD technique outcomes and patient survival. Participants (n = 766) were randomly selected from 20 of the 81 institutions in Korea treating at least 20 PD patients. Exclusion criteria included initiation of PD due to acute kidney injury, prior parathyroidectomy, or hybrid dialysis therapy within 4 months of enrollment. Patients were categorized into three groups based on the distribution of PTH level (1st tertile: 11-205, 2nd tertile: 206-392, 3rd tertile: 393-2927 pg/mL), and subgroup analysis was performed based on calcium-phosphorus product (CaXP) levels (1st tertile: 17.0-40.9, 2nd tertile: 40.9-52.5, 3rd tertile: 52.5-107.0 mg²/dL²). The primary outcome was all-cause mortality and the secondary outcome was switching to hemodialysis (HD). Results: Baseline demographics including age, sex, body mass index, comorbidities, PD vintage, and modality were comparable between groups. Serum PTH and phosphate levels were highest in the PTH 3rd tertile group, whereas serum calcium levels were lowest in this group (p<0.001). The use of calcimimetics was highest in the PTH 3rd tertile group (p<0.001), while other phosphate binders and intravenous/oral vitamin D use were comparable across all groups. In Cox proportional hazard models, no statistically significant differences were observed between the PTH tertiles regarding mortality (log-rank p-value = 0.3) or switching to HD (p = 0.9). However, subgroup analysis based on CaXP levels revealed a significant association between high CaXP and risk of switching to HD, with adjusted hazard ratio (HR) 3.38, 95% confidence interval (CI) 1.17-9.76, and p= 0.025, compared to the CaXP 2nd tertile. There was no significant association between CaXP and mortality. Conclusions: In PD patients, elevated CaXP levels were associated with an increased risk of switching to HD, whereas no significant relationship was observed between PTH or CaXP levels and mortality. These results support the importance of individualized treatment strategies based on PTH and CaXP to improve patient outcomes. Presentation: Monday, July 14, 2025