The analysis was carried out from a societal perspective; hence, we included the medical costs, the transportation costs incurred as a consequence of visiting health care institutions for outpatient and inpatient care, and the caregivers' costs during hospitalization. Since the study subjects were women who were aged 55 years or older and most were out of the labor market, productivity loss costs as a consequence of illness were not considered. NHI claims data or statistical reports were utilized to calculate the medical costs for services covered by the NHI. For the services that were not covered by the NHI, the medical costs were estimated based on the overall or disease-specific cost ratios of covered to non-covered services published by NHI corporation. The transportation and caregivers' costs were estimated based on the average numbers of outpatient visits and hospital admissions, and on the numbers of days spent in hospital per year in association with each health state, which were determined from the NHI claims data or statistical reports. All of the costs are based on the 2014 value of U.S. dollars, when $1 was approximately equal to 1,100 Korean won. Both the costs and the effects were discounted at an annual rate of 5%.
For the "healthy", "post-hip fracture" (for the third year and subsequent years after its occurrence), and "post-vertebral fracture" (for the third year and subsequent years after its occurrence) health states, we assigned an annual treatment cost for osteopenia, which included medication costs for prescription drugs (i.e., raloxifene or risedronate), and/or calcium/vitamin D supplements, and costs for routine tests to monitor the BMD status and to manage any adverse effects associated with the medication. We assumed that all patients in the treatment and the control arms underwent radiography, central bone densitometry, and tests for vitamin D levels and the bone markers every 3 years, based on practice guidelines [30 ] and consultations with local clinicians. Those in the treatment arm who received raloxifene or risedronate therapy were assumed to have undergone annual laboratory tests to assess liver function, renal function, and serum calcium, phosphate, and fasting glucose levels to monitor any adverse effects of the drugs.
The average annual costs applied for treating a fracture were estimated from the literature,[3 ] and they differed according to the type of fracture, as follows: $11,909 for non-fatal hip fractures, $5,365 for vertebral fractures, and $2,839 for other fractures. Since the vertebral and hip fracture-related costs persisted for over 1 year,[13 (link)31 (link)] we applied annual post-fracture costs to the second year after these fractures, which were $960 for a hip fracture and $905 for a vertebral fracture.[3 ] For the BC health state, an average annual cost for outpatient and inpatient services provided to patients who were diagnosed with BC was estimated using the NHI claims data from 2011 to 2013, which was $4,933. For the VTE health state, the same data and method were used as those used for the BC health state to calculate the average annual cost of treating VTE, which was $1,711.
Mortality costs were defined as those costs that were incurred during the last stages of life, and they were estimated separately depending on the cause of death, namely, hip fracture, BC, VTE, and other causes. The cost of $17,963 for a BC death was derived from a report entitled "Cost estimation from diagnosis to death of cancer patients", in which the estimated medical costs incurred during the last 12 months before death were determined for each type of cancer based on the National Cancer Surveillance data gathered from 2001 to 2005.[32 ] Since no data nor literature were available that described the mortality costs associated with deaths caused by hip fractures or VTE, we assumed that the mortality costs for these 2 conditions were equal to the average costs per hospital admission for each condition (i.e., $8,878 for a fatal hip fracture and $6,111 for a VTE death), which were estimated based on a recent NHI statistical report. For the other causes of death, the mortality costs were derived from a publication that estimated the health care costs incurred during the last 12 months before deaths from all causes in elderly Korean people in 2001.[33 ]
For the "healthy", "post-hip fracture" (for the third year and subsequent years after its occurrence), and "post-vertebral fracture" (for the third year and subsequent years after its occurrence) health states, we assigned an annual treatment cost for osteopenia, which included medication costs for prescription drugs (i.e., raloxifene or risedronate), and/or calcium/vitamin D supplements, and costs for routine tests to monitor the BMD status and to manage any adverse effects associated with the medication. We assumed that all patients in the treatment and the control arms underwent radiography, central bone densitometry, and tests for vitamin D levels and the bone markers every 3 years, based on practice guidelines [30 ] and consultations with local clinicians. Those in the treatment arm who received raloxifene or risedronate therapy were assumed to have undergone annual laboratory tests to assess liver function, renal function, and serum calcium, phosphate, and fasting glucose levels to monitor any adverse effects of the drugs.
The average annual costs applied for treating a fracture were estimated from the literature,[3 ] and they differed according to the type of fracture, as follows: $11,909 for non-fatal hip fractures, $5,365 for vertebral fractures, and $2,839 for other fractures. Since the vertebral and hip fracture-related costs persisted for over 1 year,[13 (link)31 (link)] we applied annual post-fracture costs to the second year after these fractures, which were $960 for a hip fracture and $905 for a vertebral fracture.[3 ] For the BC health state, an average annual cost for outpatient and inpatient services provided to patients who were diagnosed with BC was estimated using the NHI claims data from 2011 to 2013, which was $4,933. For the VTE health state, the same data and method were used as those used for the BC health state to calculate the average annual cost of treating VTE, which was $1,711.
Mortality costs were defined as those costs that were incurred during the last stages of life, and they were estimated separately depending on the cause of death, namely, hip fracture, BC, VTE, and other causes. The cost of $17,963 for a BC death was derived from a report entitled "Cost estimation from diagnosis to death of cancer patients", in which the estimated medical costs incurred during the last 12 months before death were determined for each type of cancer based on the National Cancer Surveillance data gathered from 2001 to 2005.[32 ] Since no data nor literature were available that described the mortality costs associated with deaths caused by hip fractures or VTE, we assumed that the mortality costs for these 2 conditions were equal to the average costs per hospital admission for each condition (i.e., $8,878 for a fatal hip fracture and $6,111 for a VTE death), which were estimated based on a recent NHI statistical report. For the other causes of death, the mortality costs were derived from a publication that estimated the health care costs incurred during the last 12 months before deaths from all causes in elderly Korean people in 2001.[33 ]
