Abstract: FR-PO154
Association Between Abnormalities of Serum Phosphate and Increased Mortality in Incident Australian and New Zealand Dialysis Patients
Session Information
- Bone and Mineral Metabolism: Phosphorus, FGF23, Vascular Calcification
November 08, 2019 | Location: Exhibit Hall, Walter E. Washington Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Bone and Mineral Metabolism
- 402 Bone and Mineral Metabolism: Clinical
Authors
- Skeat, Lee, Royal Melbourne Hospital, Melbourne, Victoria, Australia
- Ullah, Shahid, Australian and New Zealand Dialysis and Transplant Registry, Adelaide, South Australia, Australia
- McDonald, Stephen P., Australian and New Zealand Dialysis and Transplant Registry, Adelaide, South Australia, Australia
- Toussaint, Nigel David, Royal Melbourne Hospital, Melbourne, Victoria, Australia
Background
Abnormalities of mineral and bone metabolism in chronic kidney disease (CKD) are associated with increased cardiovascular and all-cause mortality. Serum phosphate is associated with adverse outcomes in a U-shaped relationship, with levels above and below the normal range associated with increased mortality in end stage renal failure. The optimal target for serum phosphate levels in CKD remains unclear. Therefore, the aim of this study was to determine if abnormalities of serum phosphate are associated with cardiovascular death and all-cause mortality in Australian and New Zealand dialysis patients.
Methods
The Australia and New Zealand Dialysis and Transplant (ANZDATA) registry was utilized to identify incident adult dialysis patients between 2005 and 2015 with ≥1 phosphate level. Phosphate levels were stratified into 3 groups; <1.6 mmol/L, 1.6-1.7mmol/L and >1.8 mmol/L. Adjusted risk of all-cause death were calculated for categories of phosphate using multivariate Cox proportional hazards regression models with phosphate levels, comorbidity and dialysis modality as time-varying covariates. Competing risk analysis was also used for cause-specific risk of death.
Results
The cohort consisted of 42,735 patients with a mean age of 58.8 (SD=15.8) years and male predominance (60.8%). Dialysis modality was 73.8% hemodialysis (HD) and 26.2% peritoneal dialysis (PD). 45.6% of patients were diabetic and 43.9% had coronary artery disease. Multivariate regression for all cause-mortality demonstrated a U-shaped relationship with highest mortality in those with phosphate <1.6 mmol/L (HR 1.17, 95%CI 1.11-1.22, p<0.001) and phosphate >1.8mmol/L (HR 1.31, 95%CI 1.24-1.38, p<0.001). Cardiovascular mortality was highest for phosphate levels >1.8mmol/L (SHR 1.25, 95%CI 1.15-1.35, p<0.001).
Conclusion
The lowest mortality was observed in patients with phosphate levels between 1.6-1.7mmol/L. Levels outside this range were associated with increased all-cause and cardiovascular mortality. This has clinical implications for target phosphate levels to reduce mortality the Australian and New Zealand dialysis population.
Funding
- Government Support - Non-U.S.