Trends in the use and outcomes of ventricular assist devices among medicare beneficiaries, 2006 through 2011

Abstract

Objectives: This study sought to examine trends in mortality, readmission, and costs among Medicare beneficiaries receiving ventricular assist devices (VADs) and associations between hospital-level procedure volume and outcomes.

Background: VADs are an option for patients with advanced heart failure, but temporal changes in outcomes and associations between facility-level volume and outcomes are poorly understood.

Methods: This is a population-based, retrospective cohort study of all fee-for-service Medicare beneficiaries with heart failure who received an implantable VAD between 2006 and 2011. We used Cox proportional hazards models to examine temporal changes in mortality, readmission, and hospital-level procedure volume.

Results: Among 2,507 patients who received a VAD at 103 centers during the study period, the in-hospital mortality decreased from 30% to 10% (p < 0.001), the 1-year mortality decreased from 42% to 26% (p < 0.001), and the all-cause readmission was frequent (82% and 81%; p = 0.70). After covariate adjustment, in-hospital and 1-year mortality decreased (p < 0.001 for both), but the all-cause readmission did not change (p = 0.82). Hospitals with a low procedure volume had higher risks of in-hospital mortality (risk ratio: 1.72; 95% confidence interval [CI]: 1.28 to 2.33) and 1-year mortality (risk ratio: 1.55; 95% CI: 1.24 to 1.93) than high-volume hospitals. Procedure volume was not associated with risk of readmission. The greatest cost was from the index hospitalization and remained unchanged ($204,020 in 2006 and $201,026 in 2011; p = 0.21).

Conclusions: Short- and long-term mortality after VAD implantation among Medicare beneficiaries improved, but readmission remained similar over time. A higher volume of VAD implants was associated with lower risk of mortality but not readmission. Costs to Medicare have not changed in recent years.

Keywords: heart failure; outcomes research; ventricular assist device.

Figure 1. Adjusted Relative Risks of Each Outcome by Annual Volume of Ventricular Assist Device Implantation

Risk ratios are shown for in-hospital mortality. Hazard ratios are shown for all other outcomes. All models control for patient characteristics, comorbid conditions, implantation admission information, and year of implantation (Table 3). p Values for differences between center volume categories by outcome are as follows: in-hospital mortality, p = 0.002; 1-year mortality, p < 0.001; 1-year all-cause readmission, p = 0.48; 1-year cardiovascular readmission, p = 0.80. CI = con fidence interval.