Cost Effectiveness Analysis with the RIVM Chronic Disease Model

Support of decision makers in health care priority setting is one of the objectives of cost effectiveness analysis. Cost effectiveness analysis presents the costs and effects of an intervention compared to an alternative in cost effectiveness ratios. The denominator of the ratio measures the health gain from the intervention and the numerator measures the costs of obtaining that health gain. The objective was to develop a methodology to be used with economic evaluations conducted with the RIVM Chronic Disease Model (CDM). Using the CDM to compute health effects and costs ensures that the same model is used for all different economic evaluations, which improves their comparability. The current report describes how cost effectiveness ratios are computed with the CDM. Special attention is paid to the selection and estimation of the costs and effects to be included during years of life gained. A cost effectiveness module was written to be attached to the RIVM Chronic Disease Model (CDM). To decide what costs and effects to include, a distinction was made between diseases causally related and diseases indirectly related to the intervention. Given this distinction the approach from Nyman (Health Economics 2004) was followed: all costs that directly produce the utility measured in the denominator have to be included in the numerator of the cost effectiveness ratio. To estimate the impact of indirectly related diseases on quality of life we use data from the Dutch Burden of Disease study. Data from the Costs of Illness study in the Netherlands were used to estimate the impact of an intervention on total health care costs. We argue that for comparison of different interventions with the RIVM CDM, one should include the costs and effects of both causally related and indirectly related diseases, since it seems impossible to isolate the precise effects of an intervention.