Economic modelling can be used to support commissioning decisions by testing the cost and benefit impact of multiple care pathway scenarios.
This allows an evidence-based argument to be articulated that underpins investment decisions.
Wolverhampton City PCT has created a comprehensive economic model in support of its Managing CVD strategic initiative. Introduced through knowledge transfer from Courtyard Group to allow the trust to develop modelling skills this methodology can now be widely used in the PCT to make robust decisions through advanced forecasting techniques. The ability to be able to make informed, evidence based decisions is a fundamental step towards becoming world class commissioners.
Firstly, the approach requires a best practice and literature review around the chosen pathway. Engagement is then required with stakeholders including clinicians, providers, finance representatives and patients to map out the current pathway.
Decision models are then built in Treeage software. Built from left to right, these models often follow a time ordering of events. Various probabilities and “rewards” are mapped out within the pathway and the population can be looped through the model as many times as required.
See diagram for an example of primary prevention choices in managing CVD.
Local data is collected to populate the model where possible, but national data and clinical opinion may also be used. This might include data such as population projections, prevalence of patient risk groups or intervention uptake and efficacy figures.
Economic models are undertaken to answer a specific question, so it is important to be clear on the end point so the model can be correctly designed. Inputs, outputs and any interventions that address the problem must be identified and included in the model to ensure the results target the initial question.
Once the “as is” pathway has been constructed, rigorous validation of the model is undertaken. Comparison of the model outcomes compared to “real life” will ensure accuracy. Sensitivity analysis then is conducted to determine how ‘sensitive’ the model is to changes in the value of parameters, and to changes in the structure. This will ensure confidence in the findings and recommendations
Stakeholder engagement is constantly required to ensure all issues are identified and potential solutions developed. Decision points within the model are varied to investigate how the pathway could potentially be improved in the future to result in better services. This is typically achieved by generating conservative, aggressive and realistic scenarios.
The CVD model represents a timeframe of 10 years to show the impact of “health checks” and the related primary and secondary prevention programmes on the following outcomes:
· CVD related events
· CVD related deaths
· Cost of the pathway by risk group
· Smoking quitters
· Known CVD prevalence in population.
This was modelled by changing the proposed coverage of health checks, evaluating 0 per cent, 20 per cent, 50 per cent and 100 per cent coverage of the target population.
The results of the model indicated:
· Implementing Health Checks significantly reduces CVD related events and deaths and thus supports the recommendation to implement health checks
· With 20 per cent health checks the known “at risk” population increases, with a resultant increase in the cost of the service and in managing these individuals
· However this is mitigated by a reduced cost for admissions
Validating the findings of the model against actual activity requires further work. The CVD pathway is complicated, and outputs from the model can only show a general trend based upon a theoretical overview of the interventions uptake. However, the approach does bring clarity to the choices available by explicitly stating the costs, consequences and patient outcomes together with the assumptions made for each of the pathway scenarios.
Outcomes for the PCT
The CVD model generated has provided data to support the recommendation to implement health checks. In addition, the PCT has been able to develop a significant staff skill set to provide an internal health economic modelling service. The ability to build models with a focused approach on PCT strategic objectives, and which produce clear and concise commissioning recommendations, will assist the trust in moving forward with its strategic commissioning goals.
Jessica Richardson and Shiona Aldridge are Information Analysts at Wolverhampton City PCT