Cost-Effectiveness of Coronary Artery Bypass Surgery Versus Medicine in Ischemic Cardiomyopathy: The STICH Randomized Clinical Trial

Abstract

Background: The STICH Randomized Clinical Trial (Surgical Treatment for Ischemic Heart Failure) demonstrated that coronary artery bypass grafting (CABG) reduced all-cause mortality rates out to 10 years compared with medical therapy alone (MED) in patients with ischemic cardiomyopathy and reduced left ventricular function (ejection fraction ≤35%). We examined the economic implications of these results.

Methods: We used a decision-analytic patient-level simulation model to estimate the lifetime costs and benefits of CABG and MED using patient-level resource use and clinical data collected in the STICH trial. Patient-level costs were calculated by applying externally derived US cost weights to resource use counts during trial follow-up. A 3% discount rate was applied to both future costs and benefits. The primary outcome was the incremental cost-effectiveness ratio assessed from the US health care sector perspective.

Results: For the CABG arm, we estimated 6.53 quality-adjusted life-years (95% CI, 5.70-7.53) and a lifetime cost of $140 059 (95% CI, $106 401 to $180 992). For the MED arm, the corresponding estimates were 5.52 (95% CI, 5.06-6.09) quality-adjusted life-years and $74 894 lifetime cost (95% CI, $58 372 to $93 541). The incremental cost-effectiveness ratio for CABG compared with MED was $63 989 per quality-adjusted life-year gained. At a societal willingness-to-pay threshold of $100 000 per quality-adjusted life-year gained, CABG was found to be economically favorable compared with MED in 87% of microsimulations.

Conclusions: In the STICH trial, in patients with ischemic cardiomyopathy and reduced left ventricular function, CABG was economically attractive relative to MED at current benchmarks for value in the United States.

Registration: URL: https://www.

Clinicaltrials: gov; Unique identifier: NCT00023595.

Keywords: cardiomyopathies; coronary artery bypass; coronary artery disease; cost-benefit analysis; costs and cost analysis.

Figure 1.

Incremental cost-effectiveness plane comparing CABG to Medical Therapy. Quadrant I represent scenarios where CABG is more costly and less effective, Quadrant II represents scenarios where CABG is more costly and effective, Quadrant III represents scenarios where CABG is less costly but more effective, and Quadrant IV represents scenarios where CABG is less costly and less effective. Abbreviations: QALY – quality-adjusted life year; WTP – willingness-to-pay; USD – United States Dollars

Figure 2.

Tornado diagram summarizing one-way sensitivity analyses on incremental cost-effectiveness ratio (cost per quality-adjusted life years gained). Grey and black bars denote the effects of the upper and lower bounds of each variable input, respectively. Abbreviations: HR, hazard ratio; QALY, quality-adjusted life year.

Figure 3.

Cost-effectiveness acceptability curves for subgroups versus base case: (A) LVEF (≤28% versus >28%) (B) Number of Vessel Disease (0–2 vessels versus 3 vessel). These figures show the probability that the cost-effectiveness ratio for surgery (versus medicine) falls below willingness-to-pay thresholds <$200,000.