For the purposes of the calculation in this report, the committee assumed that there are two phases of health states associated with IDDM. During the first 20 years, it is assumed that on average, patients experience minor discomforts and only occasional, serious health incidents. This phase was assumed to be associated with a health utility index (HUI) of .97. During the second phase, which lasts for the duration of the person’s life, there are many possible complications with varying impacts on a HUI. On average, it was assumed that this phase was associated with an HUI of .79. It was assumed that patients with IDDM, on average, experience a decrease in life expectancy of approximately 12 years. This was calculated as one-third reduction of life expectancy at the time of onset of the disease.
Table A13–1 summarizes the health care costs incurred by IDDM. For the purposes of the calculations in this report, it was assumed that 70% of patients receive conventional treatment for IDDM and 30% receive intensive treatment. It is assumed that there are costs associated with the diagnostic and very early phase of treatment, with the disease management during the 20-year period that was assumed to be free of chronic, serious sequelae, and with the disease management during the second phase, as well as costs associated with serious complications.
It will be assumed that a therapeutic vaccine strategy will only reduce costs associated with long-term management of disease and treatment of complications. The initial diagnostic phase will not be eliminated. Therefore, only the preventable costs will be described in detail. Costs incurred during the first 20 years of disease management include outpatient visits to specialists (endocrinologists and ophthalmologists, for example) and associated diagnostics, occasional visits to diabetes case managers/educators, and treatment for severe hypoglycemia in some patients. Self-care supplies are assumed to include insulin, syringes, and blood glucose monitoring supplies. It is assumed that patients in intensive treatment incur higher costs due to more frequent physician visits, diagnostics, and supplies.
Costs incurred due to serious complications associated with IDDM are also approximated for the calculations in the report. For example, it was assumed that 60% of people with IDDM will require treatment for retinopathy, renal evaluation and angiotensin-converting enzyme-inhibitor medication, and neurologic evaluation. It is assumed that 20% incur additional costs associated with blindness and end-stage renal disease. It was also assumed that a small percentage of patients will require amputation and associated costs.
The committee assumed that it will take 15 years until licensure of a therapeutic IDDM vaccine and that $360 million needs to be invested. Table 4–1