The hospitalisation costs and out-patient costs of fragility fractures

BACKGROUND

The hospitalisation costs and out-patient costs of fragility fractures

Interventions that cost more than £20,000 per every year of perfect health provided are normally deemed to be cost-ineffective in a UK setting8 which implies that the money saved from not investing in an intervention would produce more health gains for society in another disease area. Errors in the costs of fracture may thus result in inefficient usage of a limited budget. The aim of this paper was to quantify the average unit costs of fragility fractures, using where possible, a common methodology.

M D Stevenson S E Davis J A Kanis

Calculating in-patient costs of fracture Hospital Episode Statistics (HES) were used to for the average length of hospital stay during the period 2002–2004. The estimated cost assumed that the inpatient occupied an orthopaedic bed. The product of these variables was taken as the inpatient costs. The cost of an orthopaedic bed-day in the UK is not reported in standard sources,9 so that this was estimated from Swedish data where an orthopaedic bed day cost 187% more than a geriatric bed day.10 Since the cost of a geriatric bed day in the UK is £159 9 an orthopaedic bed day in the UK was thus assumed to cost £298. In some instances HES data were not applicable, for example where severe fractures are aggregated with more minor fractures or where fractures, common in adolescents with a short length of stay, are aggregated with osteoporotic fractures in the elderly. An example of the former is the ‘lower leg’ HES code, where fractures at the tibia and fibula are combined with fractures such as the ankle, which is not a site characteristic of osteoporosis. An example of the latter is forearm fractures that are common amongst children. Where the HES data was not considered applicable, Swedish lengths of stay were used since these were documented in patients aged 50 years or greater and were more specific in the fracture groupings.11 Comparisons of the length of stay following hip fracture suggest that the Swedish data may underestimate UK costs with durations of 13.0 and 26.0 days respectively for hip fracture. As such our costing estimates are likely to be conservative. In addition to costs incurred from occupying a hospital bed, other resources may be consumed. Lawrence et al. 5 captured data on operative, laboratory and radiology costs following a hip fracture, which totalled £1,946 per person. This cost has been applied to hip, pelvis and other femoral fractures. As data were unavailable for other fracture sites, we have conservatively assumed no additional in-patient costs.

Introduction Osteoporosis is a systemic skeletal disease characterised by low bone mass and micro-architectural deterioration of bone tissue with a subsequent increase in bone fragility and susceptibility to fracture.1 Although the clinical consequence of osteoporosis lies in the fractures that arise, not all fragility fractures are associated with osteoporosis. Indeed the definition of a fragility fracture is not straightforward.2 Fracture sites have been categorised as osteoporotic where the site is associated with a reduction in bone mineral density (BMD) with age and a corresponding increase in incidence of fracture.2 In women, the hip and other femoral sites, pelvis, spine, humerus, forearm, scapula, sternum, ribs, tibia and fibula have been classified as sites of osteoporotic fracture. Despite a high prevalence of osteoporosis in the elderly3 there is a paucity of data concerning the costs of fracture. The most comprehensive costing review in the UK has become dated and reports cost values for only a small number of fracture sites.4 More recent published data on the costs of hip fracture have given conflicting results; a prospective study of 100 patients admitted to hospital with hip fracture estimated the hospital admission costs at over £12,000.5 This is far in excess of the relevant Health Resource Group (HRG) code estimate6 of approximately £5,000–£7,000 per patient admission, a range depending upon complication rate and the need for hip replacement. A case control study of women with clinical vertebral fractures reported costs in the year before and after diagnosis to be £2600,7 however the methodology may allow some bias in the estimate. It is unclear to which HRG code a vertebral fracture would be allocated and thus the predicted cost using this approach is uncertain. There is little published UK data beyond these studies and the HRG costs are of uncertain validity. These data gaps are potentially important because prescribing policies in the UK are being increasingly driven by health economic analyses and a key component of cost-effectiveness is the monetary savings from fractures prevented.

Calculating out-patient costs of fracture Few data are available on the costs of out-patient care following a fracture in the UK. Data from Sweden give out-patient costs that were 11%, 9% and 31% that of in-patient costs for hip, spine and forearm respectively.10 These ratios have been used in our calculations with the same proportion for pelvis and other femoral fractures as the hip. For other fracture sites the ratio was assumed to be 10%, as this was the midpoint estimate for the hip and vertebral ratios. For patients with a diagnosed fracture that did not require hospitalisation, we assumed that the costs incurred would equal that of outpatient care following discharge of an inpatient from hospital.

M D Stevenson BSc PhD is Senior Operational Research Analyst at the School of Health and Related Research, University of Sheffield. S E Davis BSc MSc is Operational Research Analyst at the School of Health and Related Research, University of Sheffield. J A Kanis MD is Director of the WHO Collaborating Centre for Metabolic Bone Diseases, University of Sheffield Medical School, Sheffield.

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BACKGROUND

The estimated hospital and out-patient costs of an osteoporotic fracture

a

Fracture site

Percentage of fractures hospitalised

Length of stay per hospitalisation (days)

Inpatient cost per hospitalisation (£)

Average inpatient cost per fracture (£)

Average outpatient cost per fracture (£)

Total cost per fracture (£)

Hip

100%

26.0

9,694 a

9,694

1,066

10,760

Pelvis

100%

22.6

8,321 a

8,321

915

9,236

Other femoral fractures

100%

35.1

12,406 a

12,406

1,365

13,771

Spine

35%

15.0

4,470

1,565

141

1,706

Forearm

25%

5.4

1,609

402

125

527

Ribs and sternum

7%

6.4

1,907

134

13

147

Scapula

7%

6.3

1,877

131

13

144

Clavicle

7%

9.7

2,891

202

20

222

Proximal humerus and humeral shaft

32%

10.6

3,159

1,011

101

1,112

Tibia and fibula

90%

13.1

3,904

3,513

351

3,864

Including an additional £1,946 for operative, laboratory and radiology tests as detailed in Lawrence et al.4

1

estimates derived from Sweden, which although not ideal, is for reasons noted above, likely to underestimate the costs incurred within a UK setting. The estimated unit cost for hip and vertebral fracture are less than those recently reported in the literature,5,7 but are still greater than the HRG code for hip. In the case of vertebral fracture, the most appropriate HRG is not clear. Our approach is also conservative in that the costs of homehelp and nursing home admissions have been excluded from our estimates. Previously published estimates have suggested a nursing home admission rate after hip fracture of 4% at age 60 years, rising to 12% in those aged 80 years or over,3 with larger data sets from Sweden giving higher values.14 Swedish data also suggest that a small percentage of women enter a nursing home following a vertebral fracture. 

Calculating the percentage of fractures that require hospitalisation The percentage of each fracture type that required hospitalisation was taken from UK data where possible.12 Where this was not possible values were calculated using incidence data, hospitalisation data and Census data from Sweden.10,11,13 Where hospitalisation rates were available for both the UK and Sweden, the Swedish data underestimated the UK incidence of hospitalisation, for example being 35% and 29% respectively following a clinical vertebral fracture. Given this, our estimates of the costs following a fracture are likely to be conservative. The estimated costs following a fracture are given in Table 1.

Discussion In this study, we have estimated costs of fragility fractures in the UK. It was not possible, however, to derive these costs exclusively from UK-based data. Instead, several elements of the costing used

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BACKGROUND

REFERENCES 7 Puffer S, Torgeson D J, Sykes D, Brown P, Cooper C. Health Care costs of women with symptomatic vertebral fractures. Bone 2004 35: 383–386. 8 National Institute for Health and Clinical Excellence. Guides to the Methods of Technology Appraisal. NICE, 2004. 9 Netton and Curtis. The unit costs of health & social care. PSSRU: University of Kent, 2005. 10 Borgstrom F, Zethraeus N, Johnell O, Lidgren L, Ponzer S, Svensson S et al. Costs and quality of life associated with osteoporosis related fractures in Sweden. Osteoporos Int 2006 (in press). 11 Johnell O, Kanis J A, Jonsson B, Oden A, Johansson H, De Laet C. The Burden of hospitalised fractures in Sweden. Osteoporos Int 2005; 16: 222–228. 12 Kanis J A, Pitt F. Epidemiology of osteoporosis. Bone 1992; 1: S7–S15. 13 Statistics Sweden. http://www.scb.se/templates/ tableOrChart____159285.asp 14 Zethreaus N, Strom O, Borgstrom F. What is the risk of institutionalization after hip fracture? Osteoporos Int 2006; 17 (Suppl 1): S57.

1 Consensus development conference (1991). Diagnosis, prophylaxis and treatment of osteoporosis. American Journal of Medicine 1991; 90: 107–110. 2 Kanis J A, Oden A, Johnell O, Jonsson B, De Laet C, Dawson A. The burden of osteoporotic fractures: a method for setting intervention thresholds. Osteoporos Int 2001; 12: 417–427 3 Stevenson M D, Lloyd-Jones M, De Negris E, Brewer N, Davis S, Oakley J. A systematic review and economic evaluation of interventions for the Prevention and Treatment of Postmenopausal Osteoporosis. Health Technol Assess 2005; (9) 22: 1 –160. 4 Dolan P, Torgeson DJ. (1998) The cost of treating osteoporotic fractures in the United Kingdom female population. Osteoporos Int 1998; 8: 599–603 5 Lawrence T M, White C T, Wenn R and Moran C G. The current hospital costs of treating hip fractures. Injury Int J Care 2005; 36: 88–91. 6 Department of Health. http://www.dh.gov.uk/PublicationsA ndStatistics/Publications/PublicationsPolicyAndGuidance/ PublicationsPolicyAndGuidanceArticle/fs/en?CONTENT_ ID=4133221&chk=TxHkqo

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