CONTEXT: Discrete event simulation (DES) is a formalism widely used for cost-effectiveness analysis (CEA). Discretely Integrated Condition Event (DICE) Simulation is a modelling framework for CEA. It is based on two concepts: conditions, which reflect aspects that persist, and events, which occur at a point in time. The implementation most used is an Excel add-on. DICE is widely accepted because it is transparent and simplifies the coding process. Discrete event simulation networks (DESnets) are a new type of probabilistic graphical model, somewhat similar to Bayesian networks and influence diagrams. Their main contribution is the explicit use of a causal graph having different kinds of nodes for representing decisions, patients’ characteristics, costs, effectiveness, and the events that drive their evolution.

OBJECTIVES: To develop a software tool for converting DESnets (built with a graphical user interface, or GUI) into DICE models, for which there is currently no GUI.

METHODS: We have developed an algorithm that converts a DESnet into a DICE model. Its core procedure is traversing the graph from the start to the final events translating the DESnet components to DICE elements: events become event tables, and other nodes become either conditions or outputs. Links define the flow of the simulation, and which rows need to be on event tables. We have implemented it as an add-on for OpenMarkov, an open-source tool that has a graphical user interface for building DESnets. We have tested this converter on several DES models published in the literature.

RESULTS: Applying our algorithm to a DESnet we obtain a DICE model whose evaluation gives the same quantitative results as the DESnet, within stochastic variations.

CONCLUSIONS: DESnets, which are built with a graphical user interface, can be converted into DICE models, widely accepted by health economists.