EVALUATION OF CHRONIC DISEASE PREVENTION INTERVENTIONS WITH A DYNAMIC SIMULATION MODEL
Method: A dynamic simulation model is constructed using System Dynamics methodology. The model represents a typical aging population of a high-income country. There are population groups based on age: Young, Adult, Old and Older. Besides, each age group is classified based on the disease status: Healthy, Risky, Diseased and Severely Diseased. Overall we have 14 population groups and people flow among these age and disease status states. We calibrated the model for cardiovascular diseases. The risk factors contributing to the prevalence of the diseases are hypertension and obesity. We evaluate the cost effectiveness of interventions based on their success in preventing people from falling into disease groups as well as management of risk conditions.
Result: The base run (business as usual) shows increasing prevalence of diseases, followed by escalating costs due to increasing hospitalizations. Using the simulation model as a policy analysis platform, several prevention policies are tested. Total QALY increases as the prevention is applied more widely at every stage. The overall costs decrease compared to base run when only secondary prevention is applied to the risky group, but is higher for the scenarios in which tertiary prevention is applied for already diseased people.
Conclusion: If solely tertiary prevention is provided for diseased population, the total utility of people gets higher compared to business as usual, hence their quality of life is better. However, the total cost for the healthcare system is higher as well, which is not a financially sustainable outcome. Adding the secondary prevention into the system helps keeping the risk conditions under control and decreases the rate of disease onset. Hence, the costs are kept at a sustainable level.