Predictors, consequences and costs of diabetes-related lower extremity amputation complicating type 2 diabetes: the Fremantle Diabetes Study

Abstract

Aims/hypothesis: The aims of this study were to assess the incidence, predictors, consequences, and inpatient cost of lower extremity amputation (LEA) in a community-based cohort of type 2 diabetic patients.

Methods: Between 1993 and 1996, 1,294 patients with type 2 diabetes were recruited to the longitudinal, observational Fremantle Diabetes Study. LEAs and mortality from cardiac causes were monitored until 30 June 2005. Inpatient costs (in Australian dollars in year 2000), derived using a case-mix approach, were available for the period from 1 July 1993 to 30 June 2000.

Results: During follow-up 44 patients without LEA at baseline had a first-ever diabetes-related LEA, an incidence of 3.8 per 1,000 patient-years. Independent predictors of first-ever LEA included foot ulceration (hazard ratio [95% CI]: 5.56 [1.24-25.01]), an ankle brachial index < or =0.90 (2.21 [1.11-4.42]), HbA(1c) (increase of 1%: 1.30 [1.10-1.54]) and neuropathy (2.65 [1.30-5.44]). The risk of cardiac death was significantly increased in patients with LEA at baseline, although this was not an independent risk factor. The median (interquartile range) inpatient cost per LEA admission was 12,485 Australian dollars (6,037 Australian dollars-24,415 Australian dollars), with a median length of stay of 24 (10-43) days.

Conclusions/interpretation: First-ever LEAs in type 2 patients were associated with poor glycaemic control, foot ulceration and evidence of microvascular and macrovascular disease. Patients with LEA were at increased risk of cardiac death. LEAs contribute disproportionately to diabetes-related inpatient costs.