Markov models are often used to evaluate the cost-effectiveness of new healthcare interventions but they are sometimes not flexible enough to allow accurate modeling or investigation of alternative scenarios and policies. A Markov model previously demonstrated that a one-off invitation to screening for abdominal aortic aneurysm (AAA) for men aged 65 y in the UK and subsequent follow-up of identified AAAs was likely to be highly cost-effective at thresholds commonly adopted in the UK (£20,000 to £30,000 per quality adjusted life-year). However, new evidence has emerged and the decision problem has evolved to include exploration of the circumstances under which AAA screening may be cost-effective, which the Markov model is not easily able to address. A new model to handle this more complex decision problem was needed, and the case of AAA screening thus provides an illustration of the relative merits of Markov models and discrete event simulation (DES) models. An individual-level DES model was built using the R programming language to reflect possible events and pathways of individuals invited to screening v. those not invited. The model was validated against key events and cost-effectiveness, as observed in a large, randomized trial. Different screening protocol scenarios were investigated to demonstrate the flexibility of the DES. The case of AAA screening highlights the benefits of DES, particularly in the context of screening studies.
Bibliographical noteFunding Information:
Health Economics Research Group, Brunel University London, Uxbridge, Middlesex, UK (MJG); Cardiovascular Epidemiology Unit, Department of Public Health and Primary Care, University of Cambridge, Cambridge, Cambridgeshire, UK (EJ, KLM, MJS, SGT); SWAN collaborators (see Acknowledgements). Financial support for this study was provided by the UK National Institute for Health Research (NIHR) Health Technology Appraisal (HTA) programme (project number 14/179/01). The views and opinions expressed herein are those of the authors and do not necessarily reflect those of the HTA programme, NIHR, National Health Service or the Department of Health. Work done at the University of Cambridge was additionally funded by the UK Medical Research Council (MR/L003120/1), the British Heart Foundation (RG/13/13/30194), and the UK National Institute for Health Research (Cambridge Biomedical Research Centre)
© 2018, © The Author(s) 2018.
- abdominal aortic aneurysm
- decision analytic model
- discrete event simulation
- Markov model