Estimating the value of information in strategies for identifying patients at high risk of cardiovascular disease.

BACKGROUND There are many different potential strategies for identification of patients eligible for primary prevention of cardiovascular disease. The ability to use a more efficient strategy has a value. This paper models the costs and benefits of a number of identification strategies and estimates the additional value of an information-based strategy. DESIGN Modelling study. METHODS Ten-year Framingham cardiovascular risk was calculated for each individual in a population of 4471 persons aged 35-74 drawn from the Health Survey for England (equivalent to a total practice population of 12,000). Estimated Framingham risk was calculated using limited risk factor information and default risk factors. Costs of risk factor assessment were calculated using standard NHS costs. The outcomes of risk factor assessment were the total number of patients identified as eligible for treatment and the total burden of cardiovascular disease in eligible patients. Several strategies for prioritising patients for assessment were defined: opportunistic, diabetics and treated hypertensives first, ranked by estimated cardiovascular risk. The costs and outcomes of assessing increasing numbers of patients under each strategy were presented in graphical form. RESULTS To identify 70% of the burden of cardiovascular disease in this population opportunistically costs Pounds 82,102; under a 'diabetics and hypertensives first' strategy it costs Pounds 72,916; under a strategy prioritising by estimated cardiovascular risk, Pounds 27,795. The value of information in this scenario is therefore at least Pounds 45,121. CONCLUSIONS Because strategies prioritising patients by estimated cardiovascular risk dominate alternative strategies, it is possible to estimate the value of information in terms of reduced resources to achieve the same results. These resource savings largely represent savings in staff time.