Simulation of the Burden of Hyperphosphatemia in Patients on Dialysis

Patients with end-stage kidney disease (ESKD) receiving dialysis commonly develop hyperphosphatemia. The complication can lead to vascular calcification, secondary hyperparathyroidism, increased risk for fractures, and other adverse health outcomes.

To understand the role played by serum phosphate control in patients on dialysis, researchers, led by Sandeepkumar Balabbigari, built a decision tree model to simulate the population-level effect of reducing serum phosphate levels in adult patients in the United States with ESKD receiving in-center hemodialysis (n=480,516) over a 5-year time horizon. The model was described during a poster session at the American Society of Nephrology Kidney Week 2023 in a poster titled Decision Tree Model Simulating the Burden of Hyperphosphatemia in US Adult Patients With ESKD on Dialysis.

Using the US Renal Data System’s 2022 Annual Data Report, patients were assigned an initial serum phosphate level, followed by application of a reduction of 2.0 mg/dL. Based on published literature and Medicare cost data, changes in hospitalization (all-cause, cardiovascular, and fracture), parathyroidectomies, mortality, and health care costs were calculated. Direct drug costs were not addressed because the model does not specify how patients’ serum phosphate levels are reduced.

The greatest benefit seen with the modeled serum phosphate reduction was reduction in mortality, with 16,565 fewer deaths occurring over the 5-year period in the simulated population compared with a population that maintained the initial level of serum phosphate. There were 46,308 additional all-cause hospitalizations in the simulated population over the same time period, comprising the majority of an additional $165.9 million in Medicare costs.

Limitations to the model included deriving data from older retrospective studies that may not represent the current ESKD population and the inability to simulate fluctuations in serum phosphate as they would occur in reality.

In summary, the authors said, “Simulated reduction of serum phosphate levels in patients with ESKD on dialysis decreased mortality. This pronounced effect in mortality leads to an increase in all-cause hospitalization, resulting in additional Medicare costs. However, serum phosphate control is only one component of managing patients with ESKD on dialysis; there are numerous contending comorbidities and extenuating factors. These results highlight the need to continue exploring how management of patients with ESKD can provide the best patient outcomes.”

Source: Balabbigari S, Gargano M, Benjumea DW, Doan Q, Foote B. Decision tree model simulating the burden of hyperphosphatemia in US adult patients with ESKD on dialysis. TH-PO139. Abstract of a poster presented at the American Society of Nephrology Kidney Week 2023; November 2, 2023; Philadelphia, Pennsylvania. Funding was provided by Akebia Therapeutics, Inc.