Costs and cost-effectiveness of carotid stenting versus endarterectomy for patients at standard surgical risk: results from the Carotid Revascularization Endarterectomy Versus Stenting Trial (CREST)

Abstract

Background and purpose: The Carotid Revascularization Endarterectomy versus Stenting Trial (CREST) demonstrated similar rates of the primary composite end point between carotid artery stenting (CAS) and carotid endarterectomy (CEA), although the risk of stroke was higher with CAS, and the risk of myocardial infarction was higher with CEA. Given the large number of patients who are candidates for these procedures, an understanding of their relative cost and cost-effectiveness may have important implications for health care policy and treatment guidelines.

Methods: We performed a formal economic evaluation alongside the CREST trial. Costs were estimated from all trial participants over the first year of follow-up using a combination of resource use data and hospital billing data. Patient-level health use scores were obtained using data from the SF-36. We then used a Markov disease-simulation model calibrated to the CREST results to project 10-year costs and quality-adjusted life expectancy for the 2 treatment groups.

Results: Although initial procedural costs were $1025/patient higher with CAS, postprocedure costs and physician costs were lower such that total costs for the index hospitalization were similar for the CAS and CEA groups ($15 055 versus $14 816; mean difference, $239/patient; 95% CI for difference, -$297 to $775). Neither follow-up costs after discharge nor total 1-year costs differed significantly. For the CREST population, model-based projections over a 10-year time horizon demonstrated that CAS would result in a mean incremental cost of $524/patient and a reduction in quality-adjusted life expectancy of 0.008 years compared with CEA. Probabilistic sensitivity analysis demonstrated that CEA was economically attractive at an incremental cost-effectiveness threshold of $50 000/quality-adjusted life-year gained in 54% of samples, whereas CAS was economically attractive in 46%.

Conclusions: Despite slightly lower in-trial costs and lower rates of stroke with CEA compared with CAS, projected 10-year outcomes from this controlled clinical trial demonstrate only trivial differences in overall healthcare costs and quality-adjusted life expectancy between the 2 strategies. If the CREST results can be replicated in clinical practice, these findings suggest that factors other than cost-effectiveness should be considered when deciding between treatment options for carotid artery stenosis in patients at standard risk for surgical complications. Clinical Trial Registration- URL: http://clinicaltrials.gov. Unique Identifier: NCT00004732.

Figure 1

A. Scatterplot of the joint distribution of cost and QALY differences between CAS and CEA for a CREST-like population (mean age 69 years, 53% symptomatic) based on probabilistic sensitivity analysis (1000 replications). The probability that the cost and QALY difference is in each of the 4 quadrants is indicated. The diagonal line through the origin represents a cost-effectiveness threshold of $50,000/QALY gained. Each point below and to the right of this line represents an estimate derived from one model-based simulation for which CAS was found to have an estimated cost-effectiveness ratio less than the threshold ratio of $50,000 per QALY gained; points above and to the left of the line correspond to model based estimates in which the incremental cost-effectiveness ratio for CAS relative to CEA was >$50,000/QALY. The probability that CEA was economically attractive at this threshold was 54.4%. Points falling within the upper left-hand quadrant correspond to model-based results for which CAS was found to be dominated by CEA associated with both increased costs and lower effectiveness. Points falling within the lower right-hand quadrant correspond to results for which CAS was found to be a dominant therapeutic approach associated with both lower costs and increased effectiveness in terms of QALYs gained. The ellipse indicates the 95% credible interval for the joint distribution. B. Scatterplot of the joint distribution of cost and QALY differences between CAS and CEA for a 100% asymptomatic population based on probabilistic sensitivity analysis (1000 replications). The probability that the cost and QALY difference is in each of the 4 quadrants is indicated. The probability that CEA was economically attractive at this threshold was 51.4%. C. Scatterplot of the joint distribution of cost and QALY differences between CAS and CEA for a 100% symptomatic population based on probabilistic sensitivity analysis (1000 replications). The probability that the cost and QALY difference is in each of the 4 quadrants is indicated. The probability that CEA was economically attractive at this threshold was 56.3%. CEA indicates carotid endarterectomy; CAS, carotid artery stenting; QALY, quality-adjusted life-year.

Figure 1

A. Scatterplot of the joint distribution of cost and QALY differences between CAS and CEA for a CREST-like population (mean age 69 years, 53% symptomatic) based on probabilistic sensitivity analysis (1000 replications). The probability that the cost and QALY difference is in each of the 4 quadrants is indicated. The diagonal line through the origin represents a cost-effectiveness threshold of $50,000/QALY gained. Each point below and to the right of this line represents an estimate derived from one model-based simulation for which CAS was found to have an estimated cost-effectiveness ratio less than the threshold ratio of $50,000 per QALY gained; points above and to the left of the line correspond to model based estimates in which the incremental cost-effectiveness ratio for CAS relative to CEA was >$50,000/QALY. The probability that CEA was economically attractive at this threshold was 54.4%. Points falling within the upper left-hand quadrant correspond to model-based results for which CAS was found to be dominated by CEA associated with both increased costs and lower effectiveness. Points falling within the lower right-hand quadrant correspond to results for which CAS was found to be a dominant therapeutic approach associated with both lower costs and increased effectiveness in terms of QALYs gained. The ellipse indicates the 95% credible interval for the joint distribution. B. Scatterplot of the joint distribution of cost and QALY differences between CAS and CEA for a 100% asymptomatic population based on probabilistic sensitivity analysis (1000 replications). The probability that the cost and QALY difference is in each of the 4 quadrants is indicated. The probability that CEA was economically attractive at this threshold was 51.4%. C. Scatterplot of the joint distribution of cost and QALY differences between CAS and CEA for a 100% symptomatic population based on probabilistic sensitivity analysis (1000 replications). The probability that the cost and QALY difference is in each of the 4 quadrants is indicated. The probability that CEA was economically attractive at this threshold was 56.3%. CEA indicates carotid endarterectomy; CAS, carotid artery stenting; QALY, quality-adjusted life-year.

Figure 1

A. Scatterplot of the joint distribution of cost and QALY differences between CAS and CEA for a CREST-like population (mean age 69 years, 53% symptomatic) based on probabilistic sensitivity analysis (1000 replications). The probability that the cost and QALY difference is in each of the 4 quadrants is indicated. The diagonal line through the origin represents a cost-effectiveness threshold of $50,000/QALY gained. Each point below and to the right of this line represents an estimate derived from one model-based simulation for which CAS was found to have an estimated cost-effectiveness ratio less than the threshold ratio of $50,000 per QALY gained; points above and to the left of the line correspond to model based estimates in which the incremental cost-effectiveness ratio for CAS relative to CEA was >$50,000/QALY. The probability that CEA was economically attractive at this threshold was 54.4%. Points falling within the upper left-hand quadrant correspond to model-based results for which CAS was found to be dominated by CEA associated with both increased costs and lower effectiveness. Points falling within the lower right-hand quadrant correspond to results for which CAS was found to be a dominant therapeutic approach associated with both lower costs and increased effectiveness in terms of QALYs gained. The ellipse indicates the 95% credible interval for the joint distribution. B. Scatterplot of the joint distribution of cost and QALY differences between CAS and CEA for a 100% asymptomatic population based on probabilistic sensitivity analysis (1000 replications). The probability that the cost and QALY difference is in each of the 4 quadrants is indicated. The probability that CEA was economically attractive at this threshold was 51.4%. C. Scatterplot of the joint distribution of cost and QALY differences between CAS and CEA for a 100% symptomatic population based on probabilistic sensitivity analysis (1000 replications). The probability that the cost and QALY difference is in each of the 4 quadrants is indicated. The probability that CEA was economically attractive at this threshold was 56.3%. CEA indicates carotid endarterectomy; CAS, carotid artery stenting; QALY, quality-adjusted life-year.