Comparative–effectiveness research broadly encompasses any attempt to establish the benefit or harm of a diagnostic test, pharmacologic or surgical intervention, and medical service in an effort to improve patient and population health outcomes.1 In the current economic climate, healthcare budgets will remain heavily constraint for the foreseeable future thereby requiring rationale allocation of scarce healthcare resources. Despite this, national healthcare spending is growing annually and faster than the gross domestic product in many industrialised countries such as the UK, raising concerns as to the sustainability of current healthcare systems.2 Thus, stakeholders, policymakers and physicians alike are increasingly motivated—or obliged—to incorporate costs into healthcare delivery and comparative–effectiveness research. Systematically appraising the ‘value’ of healthcare services and interventions, and thereby maximising benefits per dollar spent has the potential to ensure the most efficient allocation of a healthcare budget.

Cost-effectiveness analysis formally quantifies the value of healthcare by determining the incremental costs associated with improving health outcomes; in other words, quantifying the opportunity cost of introducing a new intervention, which may then aid policy or reimbursement decisions. Comparative and cost-effectiveness analyses of health services, medical and diagnostic technologies are readily available from many health technology assessment agencies, such as the National Institute for Health and Care Excellence (NICE); these assessments are used by the UK's National Health Service (NHS) to inform reimbursement decisions.3 However, like any epidemiological tool, the accuracy, reliability and validity of cost-effectiveness analysis are a product of the quality of the data used to generate the results.4 Cost-effectiveness analyses can have a number of research designs. Historically, the most common are those that are conducted concurrently with a clinical trial, whereby economic data are collected prospectively alongside clinical outcomes. There are numerous examples of such analyses in the cardiovascular …