Health economic consequences of optimal vs. observed guideline adherence of coronary angiography in patients with suspected obstructive stable coronary artery in Germany: a microsimulation model

Aims While the number of patients with stable coronary artery disease (SCAD) is similar across European countries, Germany has the highest per capita volume of coronary angiographies (CA). This study evaluated the health economic consequences of guideline-non-adherent use of CA in patients with SCAD. Methods and results As part of the ENLIGHT-KHK trial, a prospective observational study, this microsimulation model compared the number of major adverse cardiac events (MACE) and the costs of real-world use of CA with those of (assumed) complete guideline-adherent use (according to the German National Disease Management Guideline 2019). The model considered non-invasive testing, CA, revascularization, MACE (30 days after CA), and medical costs. Model inputs were obtained from the ENLIGHT-KHK trial (i.e. patients' records, a patient questionnaire, and claims data). Incremental cost-effectiveness ratios were calculated by comparing the differences in costs and MACE avoided from the perspective of the Statutory Health Insurance (SHI). Independent on pre-test probability (PTP) of SCAD, complete guideline adherence for usage of CA would result in a slightly lower rate of MACE (-0.0017) and less cost (euro-807) per person compared with real-world guideline adherence. While cost savings were shown for moderate and low PTP (euro901 and euro502, respectively), for a high PTP, a guideline-adherent process results in slightly higher costs (euro78) compared with real-world guideline adherence. Sensitivity analyses confirmed the results. Conclusion Our analysis indicates that improving guideline adherence in clinical practice by reducing the amount of CAs in patients with SCAD would lead to cost savings for the German SHI.