Assessment of the Cost-effectiveness of Coronary Microvascular Disease Testing

This study assessed the cost effectiveness of Coronary Microvascular Disease testing using a device compared to medical treatment (standard treatment in the NHS uses drugs).  A published study was used as the main source of information supplemented by expert (cardiologist) opinion.

A timescale of one year was used as the published study only reported up to six months.  Consequently, there was limited extrapolation beyond the duration of the published study. 

A decision tree was used as the economic model with a time horizon of 3 months hence the model repeated four times after the initial decision to investigate.  Where possible, English national tariff costs were used so costs reflected true costs to the NHS.  Where tariff costs did not exist (such as for pharmaceuticals) costs from the British National Formulary were used.

Cost-effectiveness was reported as incremental cost per QALY gained.

Deterministic results (using the reported results from the study and reported costs) and probabilistic results (where the majority of inputs were as probability distributions reflecting the uncertainty in the data) were reported.  1,000 cost-effectiveness results were estimated in the probabilistic analysis.  Also, for the deterministic analysis, sensitivity to changes in the results was assessed and reported as a Tornado Plot (a diagram that looks like a tornado).  Using the probabilistic analysis, a Cost-effectiveness Plane and a Cost-effectiveness Acceptability Curve were constructed, the latter so that the likelihood of cost-effectiveness at various thresholds could be reported.  A Cost-effectiveness Plane shows the number of scenarios that fall into categories of less cost less effective, less cost more effective, more cost less effective and more cost more effective.

A report was prepared showing how the analysis was done and what the results were.  A list of references was included so that it could be seen which sources were used and when internet sources were accessed.