Impact of non-traditional phosphate binders and cinacalcet on haemodialysis patient biochemistry, pill burden and cost

Abstract

Aim: The Australian Pharmaceutical Benefits Scheme (PBS) commenced cost subsidization for haemodialysis patients of sevelamer in December 2007, cinacalcet in July 2008 and lanthanum in May 2009. To determine the impact of PBS listing of these medications, we performed a single centre cross-sectional, longitudinal study.

Methods: Dialysis parameters and biochemistry were prospectively collected at 6 monthly intervals for all prevalent haemodialysis patients from October 2007 to April 2010. Medications prescribed to manage chronic kidney disease mineral and bone disorder were recorded. Univariate regression analysis was undertaken for each variable against time.

Results: Patient numbers ranged from 87 to 114 in each period. At baseline, mean age was 68.8 ± 14.3 years, 71% male, 15.1 ± 3.5 haemodialysis hours/week and urea reduction ratio 71.9 ± 9.8%. These variables were unchanged over time. The use of sevelamer, cinacalcet and lanthanum increased (P < 0.001). There was a decrease in the use of aluminium- and calcium-based phosphate binders (P < 0.001) but no change in the use of magnesium based phosphate binders (P = 0.09) or calcitriol (P = 0.11). Serum phosphate (P = 0.13) and parathyroid hormone (PTH) (P = 0.87) were unchanged. Mean 'bone pill' burden fell from 60.3/week to 51.9/week (P = 0.02). Mean pill cost increased from Australian dollars (AUD) 12.85/patient per week to AUD 59.85/patient per week (P < 0.001).

Conclusion: The PBS subsidization of sevelamer, cinacalcet and lanthanum has changed prescribing patterns, although serum phosphate and PTH remain unchanged. These changes have been at an additional cost of AUD 2444/patient per year. Data to address clinical end-points of mortality and hospitalization is needed to determine if the cost of these newer agents is warranted.