Cost-effectiveness of different diagnostic strategies in suspected stable coronary artery disease in Portugal

Abstract

Background: Cost-effectiveness is an increasingly important factor in the choice of a test or therapy.

Objective: To assess the cost-effectiveness of various methods routinely used for the diagnosis of stable coronary disease in Portugal.

Methods: Seven diagnostic strategies were assessed. The cost-effectiveness of each strategy was defined as the cost per correct diagnosis (inclusion or exclusion of obstructive coronary artery disease) in a symptomatic patient. The cost and effectiveness of each method were assessed using Bayesian inference and decision-making tree analyses, with the pretest likelihood of disease ranging from 10% to 90%.

Results: The cost-effectiveness of diagnostic strategies was strongly dependent on the pretest likelihood of disease. In patients with a pretest likelihood of disease of ≤50%, the diagnostic algorithms, which include cardiac computed tomography angiography, were the most cost-effective. In these patients, depending on the pretest likelihood of disease and the willingness to pay for an additional correct diagnosis, computed tomography angiography may be used as a frontline test or reserved for patients with positive/inconclusive ergometric test results or a calcium score of >0. In patients with a pretest likelihood of disease of ≥ 60%, up-front invasive coronary angiography appears to be the most cost-effective strategy.

Conclusions: Diagnostic algorithms that include cardiac computed tomography angiography are the most cost-effective in symptomatic patients with suspected stable coronary artery disease and a pretest likelihood of disease of ≤50%. In high-risk patients (pretest likelihood of disease ≥ 60%), up-front invasive coronary angiography appears to be the most cost-effective strategy. In all pretest likelihoods of disease, strategies based on ischemia appear to be more expensive and less effective compared with those based on anatomical tests.

Figure 1

Cost-effectiveness plans for the diagnostic strategies according to the pretest likelihood of disease.

Figure 2

Choice of the most cost-effective diagnostic strategy according to the PLD and willingness to pay for a correct diagnosis. Once the maximum value that society is willing to pay for an additional correct diagnosis is established, the strategy that represents the best use of these resources is the one that intercepts the line of the value that society is willing to pay. For example, for a willingness to pay €1,500 per additional correct diagnosis, the best method would be ET-CCTA when the pretest likelihood of disease is 10%, CACS-CCTA when the pretest likelihood is 20%–30%, CCTA when the pretest likelihood is 40%–50%, and CATH when the pretest likelihood is ≥60%.