Diabetes-related lower-limb amputations in Australia

Design and setting: Cross-sectional analysis of a hospital morbidity dataset in Australia.

Methods: Analysis of the National Hospital Morbidity Database of all hospital separations for the ICD codes 84.10-84.19 (lower-limb amputations) and 250.0-250.9 (diabetes and its complications) for the financial years 1995-96 to 1997-98.

Main outcome measure: Number of lower-limb amputations in people with diabetes mellitus in Australia, and in each State and Territory.

Results: 7887 diabetes-related lower-limb amputations were reported during the study period, with a mean ± SD of 2629 ± 47 per year. The prevalence in Australia was 13.97 per 100 000 total population, and varied from 11.34 per 100 000 in the Australian Capital Territory to 20.68 per 100 000 in South Australia.

Conclusion: Diabetes-related lower-limb amputation poses a substantial personal and public health cost in Australia.

The National Diabetic Foot Disease Management Program, as part of the National Diabetes Strategy and Implementation Plan,⁴ has called for a 50% reduction in lower-limb amputations by the year 2005. Data on diabetes-related lower-limb amputations in Australia are lacking.⁴ The aim of my study was to identify the prevalence of diabetes-related lower-limb amputations in Australia, as well as variations among States and Territories.

The dataset for my analysis was obtained from the Australian Institute of Health and Welfare (AIHW) for the financial years 1995-96, 1996-97 and 1997-98. The AIHW obtained permission from the relevant State and Territory agencies to release the information, which did not include any personal identifying data. Information was obtained from the National Hospital Morbidity Database (compiled by the AIHW) on all separations from public and private hospitals in Australia for the International Classification of Disease (ICD)⁵ procedure codes 84.10 to 84.19 (amputations of the lower extremity) and diagnosis codes 250.0 to 250.9 (indicating diabetes and its complications) as the principal or secondary diagnoses. Information was also obtained on sex, age, ethnicity, duration of hospital stay, and State or Territory of residence of each patient who had an amputation. A spreadsheet was used to determine the number of amputations in each region and the duration of hospital stay. The data for each State and Territory were age- and sex-standardised⁶ to the estimated Australian population as at 30 June 1998.⁷ This information was then used to determine the rate for each State and Territory.

The sex differences in lower-limb amputation rates of about 2:1 for men to women reported here are consistent with previous reports,²⁰ and may be related to the levels of adherence to advice, the amount of social support, psychological factors such as denial, or a higher prevalence of the physiological risk factors for amputation such as macrovascular disease.²¹ Ethnicity is a well-recognised risk factor for lower-limb amputation,^22,23 but was not analysed in this project as two of the States/Territories would not release this information.

The duration of hospital stay has been identified as one of the main determinants of cost associated with a lower-limb amputation.¹⁷ The mean number of bed-days reported here (24.7 days) is less than the mean in the Netherlands¹⁵ (42 days) and more than that in the United States¹⁶ (15.9 days). There was a large variation among the Australian States and Territories in the mean hospital stay; South Australia has the highest prevalence of lower-limb amputation, but the shortest mean stay. Regional variations have been reported previously in New Zealand for hospital admissions for diabetic foot complications.¹⁸ Such regional variations are most likely to be due to variations in clinical practice and access to services.¹⁹

A number of shortcomings are inherent in the type of dataset analysed here. Of primary concern is the accuracy of the recording of data. Diabetes has been reported as being under-recorded on discharge records,^24,25 so the numbers reported here are most likely an underestimate. There is also concern that the dataset does not distinguish the number of multiple amputations in the same individual; this will bias the population towards the characteristics of these individuals.

A number of modifiable risk factors for diabetes-related lower-limb amputation have been identified,^26-28 including the lowering of blood pressure, improving glycaemic control and reducing or eliminating smoking. With proper foot care, patient education and provision of appropriate services, such as regular podiatric care, a reduction in the number of amputations can be achieved.⁴ A number of studies have shown the value of multidisciplinary teams in reducing amputations by up to 50%.^29-32 A reduction of this magnitude has the potential to save up to $24 million (based on the assumption that the direct cost of diabetes-related lower-limb amputations in Australia is $48 million per year⁴). However, a significant proportion of this potential saving will need to be directed to programs to prevent the amputations.

1. Nelson R, Gohdes DM, Everhart JE, et al. Lower extremity amputations in NIDDM: 12 year follow up study in Pima Indians. Diabetes Care 1998; 11: 8-16.
2. Payne CB, Scott RS, Moir C. Trigger events for acute admission to hospital for diabetic foot disease. Australas J Podiatric Med 1998; 32: 57-64.
3. Pecoraro RE, Reiber GE, Burgess EM. Pathways to diabetic amputation -- basis for prevention. Diabetes Care 1990; 13: 513-521.
4. Colagiuri S, Colagiuri R, Ward J. National Diabetes Strategy and Implementation Plan. Canberra: Diabetes Australia, 1998.
5. The International classification of diseases. 9th Revision. Clinical modification. Commission on Professional and Hospital Activities. Michigan, 1990.
6. Beaglehole R, Bonita R, Kjellstrom T. Basic epidemiology. Geneva: World Health Organization, 1993.
7. Australian Bureau of Statistics. Australian demographic statistics. Canberra: ABS, 1999. (Catalogue no. 3101.0.)
8. Fitzpatrick MC. The psychologic assessment and psychosocial recovery of the patient with an amputation. Clin Orthop 1999; 381: 98-107.
9. Frykberg RG, Arora S, Pomposelli FB, LoGerfo F. Functional outcome in elderly following lower extremity amputation. J Foot Ankle Surg 1998; 37: 181-185.
10. Lavery LA, van Houtum WH, Armstrong DG. Institutionalisation following diabetes related lower extremity amputation. Am J Med 1997; 103: 383-388.
11. Faris I, Duncan H, Young C. Factors affecting the outcome of diabetic patients with foot ulcers or gangrene. J Cardiovasc Surg 1988; 29: 736-740.
12. Ebskov LB. Relative mortality in lower limb amputees with diabetes mellitus. Prosthet Orthot Int 1996; 20: 147-152.
13. Silbert S. Amputation of the lower extremity in diabetes mellitus. Diabetes 1952; 1: 297-299.
14. Ebskov LB. Diabetic amputation and long-term survival. Int J Rehab Res 1998; 21: 403-408
15. Van Houtum WH, Lavery LA, Harkless LB. The costs of diabetes-related lower extremity amputations in the Netherlands. Diabetic Med 1995; 12: 777-781.
16. Ashry HR, Lavery LA, Armstrong DG, et al. Cost of diabetes related amputations in minorities. J Foot Ankle Surg 1998; 37: 186-190.
17. Solomon C, van Rij A, Barnett R, et al. Amputations in the surgical budget. N Z Med J 1994; 107: 78-80.
18. Payne CB, Scott RS, Moir C. Hospital discharges for diabetic foot disease in New Zealand 1980-1993. Diabetes Res Clin Pract 1998; 39: 69-74.
19. Sanders D, Coulter A, McPherson K. Variations in hospital admission rates: a review of the literature. London: King Edward's Hospital Fund, 1989.
20. Armstrong DG, Lavery LA, van Houtum WH, Harkless LB. The impact of gender on amputation. J Foot Ankle Surg 1997; 36: 66-69.
21. Vogt MT, Wolfson SK, Kuller LH. Lower extremity arterial disease and the aging process -- a review. J Clin Epidemiol 1992; 45: 529-542.
22. Lavery LA, Ashry HR, van Houtum W, et al. Variation in the incidence and proportion of diabetes related amputations in minorities. Diabetes Care 1996; 19: 48-51.
23. Simmons D, Scott D, Kenealy T, Scragg R. Foot care among diabetic patients in South Auckland. N Z Med J 1995; 108: 106-108.
24. Williams DRR, Fuller JH, Stevens LK. Validity of routinely collected hospital admissions data on diabetes. Diabetic Med 1998; 6: 320-324.
25. Phillips DE, Mann JI. Diabetes -- inpatient utilisation, costs and data validity. Dunedin 1985-9. N Z Med J 1992; 105: 313-315.
26. Moss SE, Klein R, Klein BEK. The prevalence and incidence of lower extremity amputation in a diabetic population. Arch Intern Med 1992; 152: 610-616.
27. Lehto S, Ronnemaa T, Pyorala K, Laakso M. Risk factors predicting lower extremity amputations in patients with NIDDM. Diabetes Care 1996; 19: 607-611.
28. Hamalainen H, Ronnemaa T, Halonen JP, Toikka T. Factors predicting lower extremity amputations in patients with type 1 or type 2 diabetes mellitus: a population based 7 year follow-up study. J Intern Med 1999; 246: 97-103.
29. Edmonds ME, Blundell MP, Morris ME, et al. Improved survival of the diabetic foot -- the role of a specialised foot clinic. QJM 1986; 60: 763-771.
30. Malone LM, Snyder M, Anderson G, et al. Prevention of amputation. Am J Surg 1989; 158: 520-523.
31. Ebskov LB. Epidemiology of lower extremity amputation in Denmark. Int Orthop 1991; 15: 285-288.
32. Larson J, Apelqvist J, Agardh CD, Stenstrom A. Decreasing incidence of major amputation in diabetic patients -- a consequence of a multidisciplinary foot care team approach. Diabetic Med 1995; 12: 770-777.

Reprints: Dr C B Payne, Department of Podiatry, School of Human Biosciences, Faculty of Health Sciences, La Trobe University, Bundoora, VIC 3083.
c.payneATlatrobe.edu.au

Make a comment