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

Abstract

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 drugcost drivers in hemodialysis (HD) patients, but the associationbetween PPS introduction and vitamin D therapy has been scarcely investigated. Interrupted time-series analyses. Adult US HD patients represented in the US Renal Data System between 2008 and2013. PPS implementation. 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. Segmented linear regression models of the immediate change and slope change over time of vitamin D use after PPS implementation. 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 IVvitamin 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). Incident HD patients were restricted to those 65 years or older. 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.