Cost-effectiveness of revascularization strategies: the ASCERT study

Abstract

Background: ASCERT (American College of Cardiology Foundation and the Society of Thoracic Surgeons Collaboration on the Comparative Effectiveness of Revascularization Strategies) was a large observational study designed to compare the long-term effectiveness of coronary artery bypass graft (CABG) and percutaneous coronary intervention (PCI) to treat coronary artery disease (CAD) over 4 to 5 years.

Objectives: This study examined the cost-effectiveness of CABG versus PCI for stable ischemic heart disease.

Methods: The Society of Thoracic Surgeons and American College of Cardiology Foundation databases were linked to the Centers for Medicare and Medicaid Services claims data. Costs for the index and observation period (2004 to 2008) hospitalizations were assessed by diagnosis-related group Medicare reimbursement rates; costs beyond the observation period were estimated from average Medicare participant per capita expenditure. Effectiveness was measured via mortality and life-expectancy data. Cost and effectiveness comparisons were adjusted using propensity score matching with the incremental cost-effectiveness ratio expressed as cost per quality-adjusted life-year gained.

Results: CABG patients (n = 86,244) and PCI patients (n = 103,549) were at least 65 years old with 2- or 3-vessel coronary artery disease. Adjusted costs were higher for CABG for the index hospitalization, study period, and lifetime by $10,670, $8,145, and $11,575, respectively. Patients undergoing CABG gained an adjusted average of 0.2525 and 0.3801 life-years relative to PCI over the observation period and lifetime, respectively. The life-time incremental cost-effectiveness ratio of CABG compared to PCI was $30,454/QALY gained.

Conclusions: Over a period of 4 years or longer, patients undergoing CABG had better outcomes but at higher costs than those undergoing PCI.

Keywords: coronary artery bypass graft; incremental cost-effectiveness ratio; percutaneous coronary intervention; stable ischemic heart disease.

Conflict of interest statement

No conflict of interest

Copyright © 2015 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Figures

FIGURE 1. Scatterplot of Cost and Effectiveness Differences

Scatterplot of the joint distribution of cost and effectiveness differences in the cost-effectiveness plane for the lifetime analysis. Results via (A) PSBB adjusted method and (B) the matched analytic population. Abbreviation in Central Illustration.

FIGURE 1. Scatterplot of Cost and Effectiveness Differences

Scatterplot of the joint distribution of cost and effectiveness differences in the cost-effectiveness plane for the lifetime analysis. Results via (A) PSBB adjusted method and (B) the matched analytic population. Abbreviation in Central Illustration.

FIGURE 2. Cost-effectiveness Acceptability Curve

The cost-effectiveness acceptability (CEA) curve for CABG compared to PCI demonstrates that for the lifetime analysis, the matched analytic population curve rises more steeply than that for PSBB adjusted initially, but the two converge over a lifetime. The y axis corresponds to the probability of observations below corresponding incremental cost-effectiveness (CE) ratio. PCI = percutaneous coronary intervention; other abbreviations as in Figure 2 and Central Illustration.

FIGURE 3. Sensitivity Analyses

Additional 10% to 40% increase or decrease of life years gained for CABG compared to PCI for the lifetime for the Matched Analytic Population.

FIGURE 4. Unmeasured Confounder Factor

The impact of unmeasured confounder factor.

FIGURE 5. Probabilistic Sensitivity Analyses

Plots based on Probabilistic Sensitivity Analyses for the Matched Analytic Population.

FIGURE 5. Probabilistic Sensitivity Analyses

Plots based on Probabilistic Sensitivity Analyses for the Matched Analytic Population.

CENTRAL ILLUSTRATION. Tables Demonstrating Effectiveness And Cost Of Index Over The Study Period

Upper Panel: Effectiveness: Life Year Lost for each Procedure and Life Year Gained with CABG compared with PCI unadjusted and PSBB adjusted Lower Panel: Costs of Index, period over 2004 through 2008 and lifetime by treatment group unadjusted and PSBB adjusted. PSBB = propensity score bin bootstrapping; CABG = coronary artery bypass graft.