International variations in serum PTH and calcium levels and their mortality associations in peritoneal dialysis...

Area of Science:

• Nephrology
• Endocrinology
• Public Health

Background:

• Mineral bone disorder (MBD) is a significant complication in chronic kidney disease (CKD), impacting patient health and survival.
• MBD in peritoneal dialysis (PD) patients remains understudied, despite its association with increased fractures, vascular calcification, and cardiovascular disease.
• This study focuses on calcium and parathyroid hormone (PTH) control and their mortality associations specifically within the PD patient population.

Purpose of the Study:

• To describe calcium and parathyroid hormone (PTH) control in patients undergoing peritoneal dialysis (PD).
• To investigate the relationship between baseline PTH and albumin-adjusted calcium (calcium ^Alb) levels and all-cause mortality in PD patients.
• To examine variations in MBD therapy prescriptions across different countries.

Main Methods:

• Utilized data from the prospective Peritoneal Dialysis Outcomes and Practice Patterns Study (2014-2022) across eight countries.
• Analyzed baseline PTH and calcium ^Alb levels in 12,642 and 14,244 PD patients, respectively, using Cox regression.
• Adjusted mortality analyses for confounders including serum phosphorus and alkaline phosphatase.

Main Results:

• The PTH/mortality relationship exhibited a U-shape, with the lowest risk observed at PTH levels of 300-599 pg/mL.
• Mortality risk was approximately 20% higher for serum calcium ^Alb levels of 9.6+ mg/dL compared to 8.4-<9.6 mg/dL.
• Significant variations in MBD therapy prescriptions were noted among participating countries.

Conclusions:

• A substantial proportion of PD patients exhibit calcium and/or PTH levels associated with significantly increased mortality risk.
• These findings underscore the urgent need for improved MBD management strategies in PD patients to enhance patient outcomes.
• The study highlights potential confounding factors but emphasizes the critical concern for MBD management in PD, especially considering high phosphorus levels.