In 2015, Medicare paid more than $1.5 billion for phosphate binders for patients on dialysis in the United States and for patients with chronic kidney disease (CKD). Previous analyses have shown that phosphate binders are the most commonly used medications for treatment of CKD-mineral and bone disorder (MBD). The analyses also demonstrated a faster increase in Part D costs for CKD-MBD medications (phosphate binders, vitamin D analogues, and cinaclacet) for patients on dialysis from 2007 to 2010 than costs for all Part D medications (36% vs 22%). The increases occurred despite relatively stable use within medication classes. For 2014, phosphate binders represented 37% of all Medicare Part D expenditures for dialysis patients.
In a policy forum perspective article in the American Journal of Kidney Diseases [2018;71(2):246-253], Wendy L. St Peter, PharmD, Lori D. Wazny, PharmD, and Eric D. Weinhandl, PhD, MS, provided an update on trends in phosphate-binder use, calcium and phosphorous values, and costs for dialysis patients covered by Medicare. The authors utilized primary data to evaluate the trends and then reviewed the literature on the effectiveness and cost-effectiveness of phosphate binders in that patient population.
Use, Costs, and Effectiveness
From 2008 to 2013, the number of patients on dialysis who were dispensed at least one Part-D covered phosphate binder increased 29% (from 204,208 to 263,404); corresponding percentages of phosphate binder users were stable at approximately 76%. Over time, there was as shift in use of specific phosphate binders. There was a decrease in use of calcium acetate from 38% to 34%; no change in use of non-calcium containing phosphate binders; an increase in use of sevelamer carbonate; and a decrease in use of sevelamer hydrochloride (by 2013, only 7% of dialysis patients were dispensed sevelamer hydrochloride). Part D does not cover calcium carbonate; it is not included in the analyses.
There was a 118% increase in annual Medicare costs for phosphate binders between 2008 and 2013 (an increase of $486 million). Of the total cost in 2013, sevelamer carbonate and sevelamer hydrochloride together accounted for $741 million (83% of phosphate binder costs covered by Part D for Medicare beneficiaries on dialysis). For the same time period (2008-2013), total costs per user-year for phosphate binders increased from $2221 to $3716 (a 67% cumulative increase, or a 10.8% compound annual growth rate). Total costs per user-year for all other drugs covered by Part D cumulatively increased by 21% during that time period.
Phosphate Binder Regulation
The percentages of Medicare Part D beneficiaries using phosphate binders was steady from 2008 through 2013. However, there was an increase in patient prevalence, accounting for the increase in Medicare costs for phosphate binders. It does not account for the increased costs of phosphate binders outpacing costs related to all other Part D-covered drugs for dialysis patients during the same time period.
Phosphate binders are approved by the US FDA for control of serum phosphorous concentrations in dialysis patients and/or patients with CKD. Despite the increased costs, the researchers note, there has not been improvement in control.
There are few available data from randomized clinical trials demonstrating that: (1) lower compared with higher phosphorous concentration of (2) therapy with any phosphate binder reduces hard clinical end points compared with placebo or another phosphate binder. The authors suggest that the FDA “should consider requiring adequately powered placebo-controlled blinded trials of sufficient duration to evaluate hard clinical outcomes and not simply phosphorus concentration reduction…Because no clinical trials of phosphate binders have been powered adequately to assess cardiovascular outcomes, the FDA should consider convening an advisory committee to determine whether cardiovascular risk should be addressed during the drug development phase of new phosphate binders.
“Given that Medicare is the main payer for phosphate binders for US dialysis patients and the skyrocketing Medicare costs, the Centers for Medicare & Medicaid Services should have a vested interest in answering the question of whether maintaining lower versus higher phosphate concentrations improves hard clinical outcomes, and if so, whether particular phosphate binders are superior to placebo or other binders in improving these outcomes. A validated method for assessing adherence is essential to understanding effects on outcomes. Trials should be consistently designed and conducted so that future meta-analyses and valid cost-effectiveness analysis will be possible. This is the only way to know if we are getting enough bang for our collective buck for phosphate binders in dialysis patients,” they concluded.
- Phosphate binders are the most commonly used medications for chronic kidney disease-mineral bone disorder in patients on dialysis; Medicare Part D costs for phosphate binders increased faster than costs for all Part D medications from 2007 to 2010.
- Between 2008 and 2013, total costs per user-year for phosphate binders increased 67% compared with a 21% increase for all other Part D medications for dialysis patients.
- The authors suggest that the US FDA fund clinical trials to determine whether phosphate concentration, phopphate-binder therapy, and phosphate-binder type reduces clinical outcomes in dialysis patients.