4.10. Other modelling issues

Due to the data constraints, for individuals under age 18, all costs are assumed to be zero. This is not likely to be a major concern because we are most interested in modelling costs for diseases that have very low prevalence in this age group.

In general, we used cost estimates split by two broad age groups: 18-64 and 65+ years, to ensure that we have sufficient sample size for parameter estimation. We have made the exception for myocardial infarction, breast cancer, diabetes, COPD and depression, using the narrower age groups (18-39; 40-49; 50-59; 60-64; 65-69; 70-74; 75-79; 80-84; 85-89; 90+). This was made possible by the larger sample size owing to greater than 1% prevalence of these conditions in the population.

For the people who died, in the last year of life, it is assumed that they will accumulate only half of their extra residual and disease costs.