The cost of creating superbugs: A cost-utility analysis of prophylactic Ceftriaxone for prevention of complications in acute ischemic stroke incorporating the external cost of antibiotic resistance

Abstract

Background: Antibiotic resistance is an increasingly important issue, with many authors and public health organizations emphasizing the urgent need for action. Antibiotic resistance is a negative externality and relevant cost associated with antibiotic use. However, to the best of my knowledge, no economic evaluation to date has included the negative externality of antibiotic consumption as a cost component. This thesis had two main aims. First, to explore methods to include the negative externality of antibiotics consumption in economic evaluation. Second, to perform an economic evaluation as a case study to showcase and implement this method in practice. As a part of the PRECIOUS research project, a cost-utility analysis of novel stroke treatment that includes prophylactic antibiotics was chosen as the case study. Methods: A cost-utility analysis of IV-tPA with Ceftriaxone prophylaxis compared with IV-tPA only. A Markov model was used to simulate a theoretical patient cohort of elderly stroke patients and estimate the external costs of antibiotic resistance. Results: Without accounting for external cost of antibiotic resistance, IV-tPA with Ceftriaxone prophylaxis was more effective and cost-saving compared with IV-tPA only. The ICER was significantly impacted by the inclusion of externality. After inclusion of external costs Ceftriaxone was no longer cost-saving. The inclusion of externality also introduced decision uncertainty at low levels of WTP per QALY. Conclusion: External costs of antibiotic resistance was included using a simple, but crude method. The true extent of externality was likely underestimated in this study. Accounting for externality would not change the decision outcome of this cost-utility analysis. However, results warrant further research to refine the data and methods used to include the external costs of antibiotic resistance for use in future economic evaluations.