Direct and indirect costs
To estimate the financial burden, both direct and indirect costs related to osteoporotic fractures have been considered, except costs for rehabilitation. Direct costs in general encompass medical as well as non-medical costs directly related to the causative disease. Accordingly, we included costs for pharmacotherapy, hospital and nursing home, as well as costs for (follow-up) radiographs, wheel chairs, crutches, transport to outpatient settings etc. In contrast, indirect costs, sometimes also referred to as productivity costs, are a measure of present and/or future productivity losses caused by a disease. Indirect costs were calculated according to the human capital approach . Hence, we included productivity loss due to absence from work as well as costs for early retirement and costs of informal (unpaid) care provided by family members and/or other persons. We decided to draw on the human capital approach rather than on the friction-cost method because the former is grounded in neoclassical economic theory while the latter is not . Moreover, Austria’s unemployment rate in 2008 was among the lowest in Europe. This fact served as an additional argument to not employ the friction cost approach in our study. Only in case of labour market imperfections and high unemployment the friction cost approach might be considered as a feasible alternative.
Source and quantity of costs following fracture
Source and quantity of costs following the first year after fracture have been obtained from the Austrian branch of the International Costs and Utilities Related to Osteoporotic Fractures Study (ICUROS). The ICUROS is an ongoing international study supported by the International Osteoporosis Foundation (IOF) which aims at assessing the consequences of osteoporotic fractures in terms of costs and health related quality of life (QOL) in a standardized form, making results comparable among the different participating countries worldwide [data unpublished, http://www.medscinet.com/icuros/project.aspx]. To assess sources and quantities of costs for the prevailing study, an interim analysis of the Austrian study arm of the ICUROS was performed. Data were extracted from a total of 916 patients who had finished phase II of the study, i.e. who had at least one follow-up interview within the first year after the fracture. Of these patients, 488 had a hip fracture, 158 had a clinical vertebral fracture, 140 had distal forearm fracture, and 122 had a fracture of the humerus. Information on following parameters was obtained: Number of outpatient visits at the primary care level and/or hospital, number of home visits, number of phone counselling, use and dosage of drugs, number and type of community services and other services (e.g. nursing), information on working situation, type of employment (also part or full-time), number of sick days, informal care, information on investments directly or indirectly caused by fracture and its consequences (wheelchair, walking aids, modifications to house/apartment, special utensils for personal hygiene etc.).
Depending on the source of costs, costs themselves where then obtained from institutions and services which most likely would have readily accessible the according information.
Number of patients with osteoporotic fractures
The number of patients with osteoporotic fractures was calculated for the entire Austrian population. The following types of fracture were included: hip fracture, humeral fracture, clinical (symptomatic) vertebral fracture, distal forearm fracture, and rib fracture. Since most but not all of the fractures may have been due to osteoporosis per se, specific weighting factors have been applied .
The number of patients with hip fractures in Austria in 2008 was obtained from the Austrian Hospital Discharge Register (AHDR) for the entire population. As one hundred percent of people who sustain a hip fracture are admitted to hospitals, the number obtained from the AHDR is equivalent to the total number of patients who sustained a hip fracture in 2008. To correct for possible multiple registrations (within a year after admission) for the same diagnosis, a correction factor (0.9) has been applied. These data have been published recently .
The number of patients with humeral fractures admitted to hospitals in Austria in 2008 has been drawn from the AHDR. In contrast to patients who sustain a fracture of the hip, only a part of those who sustain a humeral fracture are admitted to hospitals. The proportion of patients who have been treated in an outpatient setting was assessed by extracting databases from seven large Trauma Units in Austria who covered about 20% of all humeral fractures that occurred in 2008 nationwide. Based on the data obtained from these Trauma Units, it has been estimated that the proportion of humeral fracture patients who have been admitted to hospitals (and hence captured by the AHDR) is 57%. An according correction factor was applied.
Clinical vertebral fractures
The number of patients with clinical vertebral fractures who have been admitted to hospitals in Austria in 2008 was derived from the AHDR. However, since not all patients with clinical vertebral fractures are admitted to hospitals, this number would reflect only part of the total number of patients. According to data derived from a recently published Swedish study, it was estimated that the number of patients with clinical vertebral fractures admitted to hospitals account for approximately 10% of all female patients with clinical vertebral fractures, and 15% of all male patients nationwide . To estimate the total number of Austrian patients who sustained a clinical vertebral fracture, an according correction factor was applied.
The number of patients with forearm fractures who have been admitted to hospitals in Austria in 2008 was derived from the AHDR. Again, this number would reflect only part of the total number of patients who had sustained a forearm fracture, since many of these patients may be treated in an outpatient setting. Several studies have indicated that in general only approximately 20% of patients with distal forearm fractures are admitted to hospitals and treated in an inpatient setting, e.g. for the purpose of operative intervention [17–19]. To estimate the total number of Austrian patients who sustained a forearm fracture, the according correction factor was applied.
The number of patients with rib fractures who have been admitted to hospitals in 2008 in Austria was derived from the AHDR. Again, this number would reflect only part of the total number of patients who had sustained a rib fracture that came to clinical attention . In a Finnish population it has been estimated that only about 10% of all rib fractures after minimal trauma would be admitted to hospitals . To estimate the total number of Austrian patients with low trauma rib fractures, the according correction factor was applied.
Costs of hospitalization
Data on the average duration of stay in hospital per fracture type (i.e. hip, clinical vertebral, humerus, forearm, ribs) was obtained from the ICUROS, and/or provided by Statistics Austria. To estimate the total number of days of stay in hospital, the number of days of stay in hospitals per fracture type was multiplied by the number of patients who had sustained an according fracture under consideration of correction factors where applicable (see above), and results obtained from the different fracture types were then summarized.
Data on costs per day of stay in hospital were provided by the Austrian Federal Ministry of Health. In average, in 2008 the cost of one day spent in an orthopaedic or trauma department of an Austrian Hospital was € 592 (including medications, nutrition etc.). This value was then multiplied by the total calculated hospital days of stay which have been caused by osteoporotic fractures.
Costs of outpatient treatment
Costs incurred through consultations of practicing and/or hospital employed specialists (e.g. orthopaedists) were calculated using data provided by the Central Association of Austrian Social Security Institutions. In average, costs for consultation of an orthopaedist in a hospital outpatient clinic were € 53.55 per consultation, and costs for consultation of an orthopaedist in the primary care setting were € 73.10 per consultation. These costs were then multiplied by the according number of consultations.
Other medical and non-medical costs
Number of radiographs, physical therapies and transportation as consequences of a fracture were obtained from the ICUROS database. Unit costs for radiographs, bone mineral density measurement (Dual x-ray Absorptiometry [DXA]) and physical therapy were provided by the Central Association of Austrian Social Security Institutions. Average unit cost of BMD-measurement (lumbar spine and hip) was estimated at € 35.00. Average unit cost of a radiograph was estimated at € 80.40, and the average unit cost of a standard physical therapy was estimated at € 30.00. Information on costs of non-emergency transportation was provided by a common Austrian Ambulance Service (Samariterbund). Mean cost per transportation was estimated at € 57.00. Unit cost for wheelchairs, wheeled walkers, crutches, ramps, cranes etc. were obtained through information provided by the according retail stores.
Costs of pharmacotherapy
Costs of pharmacotherapy were calculated based on the estimated number of incident osteoporotic fractures in Austria in 2008. However, since data from the Austrian study arm of the ICUROS indicates that only about 22% of patients with recent osteoporotic fracture would receive adequate osteoporosis treatment (data unpublished), estimation of costs of pharmacotherapy only took into account this proportion of patients. Furthermore, to further improve accuracy of estimation, we also considered the proportional distribution of osteoporosis drugs as derived from the ICUROS database. For estimation of costs incurred by analgesics, calcium and vitamin D, again data from the ICUROS were extracted which indicated that ~37% of patients following an osteoporotic fracture would receive analgesic therapy, and 40% would receive calcium and vitamin D. Drug prices were based on the 2008 version of the Austrian EKO (Erstattungskodex) .
Costs of nursing and informal care
Number of hours of nursing care and informal care as a consequence of osteoporotic fracture was obtained from the Austrian ICUROS database. Information on costs of nursing was provided by Statistics Austria, and the average cost of one hour of nursing was estimated at € 30. Information on number of hours of informal (unpaid) care provided by family members or other persons as a consequence of osteoporotic fracture was obtained from the Austrian ICUROS database. Cost of one hour of informal care was estimated at € 27.50, reflecting the average hourly wage of an Austrian employee .
Costs of absenteeism
Data regarding number and costs of sick-days due to osteoporotic fractures in the Austrian population were provided by Statistics Austria and the Austrian Pension Insurance Authority. In total, 3.490 men and 2.336 women had been on sick-leave due to such conditions in 2008. The average number of sick-days in these patients was 16.3 in men, and 18.9 in women. To estimate the costs of absenteeism, the mean annual gross salary per capita of Austrian employees was divided by 220 working days, and this number was then multiplied by the average number of osteoporotic-fracture associated sick-days. However, it should be considered that the costs estimated as described above, would rather underestimate the true costs, as wages alone would not include for example loss of profit or the employer’s contribution to the Austrian Social Security institutions. Therefore, to estimate the total loss of added value incurred through absenteeism, data from the official Input–output Table (IOT) were extracted. Data were provided by Statistics Austria. By means of this analysis, information on so called second round effects was obtained. Second round effects typically occur due to reduced productivity in one company or institution (e.g. caused by absenteeism of employees), with the consequence of decreasing output in supplying companies or institutions .
Costs of early retirement
According to data provided by the Federal Ministry of Labour, Social Affairs and Consumer Protection, as well as Statistics Austria, a total of 338.462 Austrians were registered as in early retirement due to disability (also referred to as disability pension) in 2008 , and 25.146 cases of early retirement have been newly registered throughout the year 2008. The average annual cost of early retirement per capita in 2008 was €13.395. Musculoskeletal and connective tissue diseases have been the underlying cause in 6.989 cases, of whom 0.338% was due to osteoporosis-related conditions . Accordingly, the total number of disability pension cases due to osteoporosis-related conditions in 2008, was estimated at approximately 1.444. To calculate the total costs of early retirement due to osteoporosis-related conditions, the estimated number of cases was multiplied with the average annual costs per capita to come up with an estimated amount of € 19.3 million.