Hyperkalaemia and potassium binders: Retrospective observational analysis looking at the efficacy and cost effectiveness of calcium polystyrene sulfonate and sodium zirconium cyclosilicate

What is Known and Objective

Hyperkalaemia is a common medical emergency in patients admitted to hospital. There is a limited evidence base supporting some of the commonly applied treatment strategies. Although, NICE has recommended the use of sodium zirconium cyclosilicate (SZC) (TA599) and patiromer (TA623) in both acute and chronic hyperkalaemia, there is a limited evidence base for their use in acute hyperkalaemia in the hospital setting, particularly when compared to the present standard of care calcium polystyrene sulfonate (CPS).

Methods

A retrospective review of the electronic patient record system across our hospital over a 6-month period identified 138 patients who received either SZC (65 patients) or CPS (73 patients) to manage hyperkalaemia, investigating their efficacy and cost effectiveness. Results were analysed using simple descriptive statistics. Based on the results a naïve cost comparison between the two drugs was made.

Results and Discussion

CPS and SZC both effectively reduced plasm potassium concentrations in patients with hyperkalaemia (6.07 and 6.03 mmol/L respectively) by 1.17 mmol/L and 1.24 mmol/L taking a similar amount of time to work (2.97 days vs. 3 days). The principle causes of hyperkalaemia identified were acute kidney injury, medication, and chronic kidney disease. Cost comparison analysis which took into account raw product price and time needed to dispense medications revealed that CPS has slightly better cost effectiveness compared to SZC albeit at a cost of increased staff input.

What is New and Conclusion

Both CPS and SZC were equally effective at lowering acutely raised potassium concentrations. The cost difference between the two products appears to be small. Claims regarding the benefits of newer agents over older established medications need to be properly explored in randomized trials rather than being based on small scale non-comparative studies.