APPENDIX C

THE STATE BURDEN OF FRACTURE MODEL

METHODOLOGY

The state burden of illness model was developed by Merck and Company and presented at the 1996 annual meeting of the American Society of Bone and Mineral Research. The model combined estimates of fracture risk with Census Bureau projections for the female populations of each state to project hip, wrist, and vertebral fractures for 1995-2015.

Two sources were used to calculate estimated fracture risks: (1) epidemiological studies conducted in Rochester, Minnesota, and reported upon in the 1980s and (2) a 5% sampling of Medicare patients compiled between 1986 and 1990. The Rochester data involved hip, vertebral, and wrist fractures among white women only and are reported in five-year age intervals. The Medicare data are reported in five-year intervals starting with age 65 and by race (white, black, and other/unknown) and do not include estimates for vertebral fractures.

The Census Bureau population projections were made for 1993 and five-year intervals beginning with 1995. The numbers used for intervening years were derived through extrapolation of the projections. Only women aged 45 and older were included in the model; five age groups were therefore extracted from the Census estimates: 45-54, 55-64, 65-74, 75-84, and 85+.

For each state, the projected fracture numbers and rates were calculated by multiplying the population within a specific age group by the corresponding fracture rates from the sources described above. The additional projections of hip fracture mortality were derived using mortality data from the same sources. Total hip fracture mortality rates represent all those women who are expected to die within one year following their hip fracture. It would be expected that some of these women would have died during that year of other causes; "excess" deaths represent the additional deaths that are directly related to the hip fracture.

The state burden of fracture model also contains projections of fracture costs over the same time period. The model assumes the cost of a hip fracture to be $24,677, which includes hospital costs, rehabilitation costs, and nursing home stays up to one year following the fracture. The model also assumes the cost of a wrist fracture to be $350 and that of a vertebral fracture to be $50. The projections assumed an annual 5% rate of inflation in medical care costs. Because our estimates for hospital costs alone for the treatment of wrist and vertebral fractures far exceeded the model's assumptions, we chose not to include this segment of the model in our analysis.

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