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.
Copyright © 2018 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.