Association of Medicare's Bundled Payment Reform With Changes in Use of Vitamin D Among Patients Receiving Maintenance Hemodialysis: An Interrupted Time-Series Analysis

Am J Kidney Dis. 2018 Aug;72(2):178-187. doi: 10.1053/j.ajkd.2018.03.027. Epub 2018 Jun 8.


Background & rationale: Medicare's 2011 prospective payment system (PPS) was introduced to curb overuse of separately billable injectable drugs. After epoietin, intravenous (IV) vitamin D analogues are the biggest drug cost drivers in hemodialysis (HD) patients, but the association between PPS introduction and vitamin D therapy has been scarcely investigated.

Study design: Interrupted time-series analyses.

Setting & participants: Adult US HD patients represented in the US Renal Data System between 2008 and 2013.

Exposures: PPS implementation.

Outcomes: The cumulative dose of IV vitamin D analogues (paricalcitol equivalents) per patient per calendar quarter in prevalent HD patients. The average starting dose of IV vitamin D analogues and quarterly rates of new vitamin D use (initiations/100 person-months) in incident HD patients within 90 days of beginning HD therapy.

Analytical approach: Segmented linear regression models of the immediate change and slope change over time of vitamin D use after PPS implementation.

Results: Among 359,600 prevalent HD patients, IV vitamin D analogues accounted for 99% of the total use, and this trend was unchanged over time. PPS resulted in an immediate 7% decline in the average dose of IV vitamin D analogues (average baseline dose = 186.5 μg per quarter; immediate change = -13.5 μg [P < 0.001]; slope change = 0.43 per quarter [P = 0.3]) and in the starting dose of IV vitamin D analogues in incident HD patients (average baseline starting dose = 5.22 μg; immediate change = -0.40 μg [P < 0.001]; slope change = -0.03 per quarter [P = 0.03]). The baseline rate of vitamin D therapy initiation among 99,970 incident HD patients was 44.9/100 person-months and decreased over time, even before PPS implementation (pre-PPS β = -0.46/100 person-months [P < 0.001]; slope change = -0.19/100 person-months [P = 0.2]). PPS implementation was associated with an immediate change in initiation levels (by -4.5/100 person-months; P < 0.001).

Limitations: Incident HD patients were restricted to those 65 years or older.

Conclusion: PPS implementation was associated with a 7% reduction in the average dose and starting dose of IV vitamin D analogues and a 10% reduction in the rate of vitamin D therapy initiation.

Keywords: Medicare; United States Renal Data System (USRDS); Vitamin D; bundled payment; calcitriol; doxercalciferol; drug costs; end-stage renal disease (ESRD); hemodialysis (HD); interrupted time-series; intravenous preparation; observational; oral preparation; paricalcitol; payment reform; prospective payment system (PPS); vitamin D analogs.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Cohort Studies
  • Drug Administration Schedule
  • Female
  • Humans
  • Infusions, Intravenous
  • Interrupted Time Series Analysis / methods*
  • Kidney Failure, Chronic / economics*
  • Kidney Failure, Chronic / epidemiology
  • Kidney Failure, Chronic / therapy
  • Male
  • Medicare / economics*
  • Middle Aged
  • Prospective Payment System / economics*
  • Prospective Payment System / trends
  • Renal Dialysis / economics*
  • Renal Dialysis / methods
  • United States / epidemiology
  • Vitamin D / administration & dosage
  • Vitamin D / economics*


  • Vitamin D