Abstract
Introduction
Hyperphosphatemia (serum phosphorus >5.5 mg/dL) in hemodialysis patients is a key factor in mineral and bone disorders and is associated with increased hospitalization and mortality risks. Treatment with oral phosphate binders offers limited benefit in achieving target serum phosphorus concentrations due to high daily pill burden (7–10 pills/day) and associated poor medication adherence. The economic value of improving phosphate binder adherence and increasing percent time in range (PTR) for target phosphorus concentrations has not been previously assessed in dialysis patients. The current retrospective analysis was conducted to summarize health care cost savings to United States (US) payers associated with improved phosphate binder adherence and increased PTR for target phosphorus concentrations in adult end-stage renal disease (ESRD) patients receiving hemodialysis therapy.
Methods
Phosphate binder adherence and PTR were derived from hemodialysis patients who were treated at a large dialysis organization between January 2007 and December 2011. Cost model inputs were derived from US Renal Data System data between July 2007 and December 2009. A cost-offset model was constructed to estimate monthly and annual incremental health care costs (total Medicare; inpatient, outpatient, and Medicare Part B) associated with different levels of phosphate binder adherence and PTR. Model inputs included number of ESRD patients, population adherence to phosphate binders, PTR associated with adherence to phosphate binders, and per-patient per-month cost associated with PTR. A base case model estimated monthly and annual costs of phosphate binder therapy in the population using estimated model inputs. The estimated adherence rate was used to determine number of patients in compliant and noncompliant groups. Monthly costs were calculated as the sum of per-patient per-month cost times the number of patients in adherent and nonadherent groups. Annual costs were monthly costs times 12 and assumed the same level of adherence, PTR, and per-patient per-month costs over time. To study the impact of improving phosphate binder adherence and PTR on cost outcomes, we hypothetically and simultaneously increased both base phosphate binders adherence and PTR for adherent patients (adherence/PTR: 10/20%, 20/40%, 30/60%). Monthly and annual costs were derived for each scenario and compared against the results of the base case model. One-way sensitivity analysis was performed to test model robustness.
Results
The base case model estimated total Medicare and inpatient costs of $5,152,342 and $1,435,644, respectively (N = 1,000). When base case model costs were compared to results of each extended model scenario, overall Medicare cost savings (range 0.3–1.9%) and inpatient cost savings (range 1.2–5.7%) were observed. The one-way sensitivity analysis indicated that results were sensitive to PTR for adherent and nonadherent patients and the factor used to increase adherence rate and PTR associated with adherence in the hypothetical scenarios. However, cost savings in overall Medicare costs and inpatient costs were still noted.
Conclusion
Increasing phosphate binder adherence and improving phosphorus control were associated with increased cost savings in total Medicare costs and inpatient costs.
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Acknowledgments
This study and the associated article processing charges were sponsored and funded by Vifor Pharma. DaVita Clinical Research® (DCR®) provided clinical data, analysis, and writing support for this research project. Christopher A. Graybill, PhD (DCR®), provided editorial support for this manuscript. Vifor Pharma funded the support for all of these activities. All named authors meet the ICMJE criteria for authorship for this manuscript, take responsibility for the integrity of the work as a whole, and have given final approval for the version to be published.
A portion of these data were presented as a poster at the 2013 Academy of Managed Care Pharmacy Educational Conference in San Antonio, Texas, USA, on October 16, 2013.
Conflict of interest
At the time of analysis: Karthik Ramakrishnan was an employee of DaVita Clinical Research; Deborah Lubeck was an employee of DaVita Clinical Research; Steven Wang was an employee of DaVita Clinical Research; Jennifer Deuson was an employee of DaVita Clinical Research; Ami Claxton was an employee of DaVita Clinical Research; Peter Braunhofer was an employee of Vifor Pharma; and Britt Newsome was an employee of Denver Nephrology.
Compliance with ethics guidelines
The analysis in this article is based on previously conducted studies, and does not involve any new studies of human or animal subjects performed by any of the authors.
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Ramakrishnan, K., Braunhofer, P., Newsome, B. et al. The Economic Impact of Improving Phosphate Binder Therapy Adherence and Attainment of Guideline Phosphorus Goals in Hemodialysis Patients: a Medicare Cost-Offset Model. Adv Ther 31, 1272–1286 (2014). https://doi.org/10.1007/s12325-014-0170-4
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DOI: https://doi.org/10.1007/s12325-014-0170-4