Geographic Variation of the Incidence Rate of Lower Limb Amputation in Australia from 2007-12

Abstract

In Australia, little is known about how the incidence rate (IR) of lower limb amputation (LLA) varies across the country. While studies in other economically developed countries have shown considerable geographic variation in the IR-LLA, mostly these have not considered whether the effect of common risk factors are the same across regions. Mapping variation of the IR-LLA, and the effect of common risk factors, is an important first step to focus research into areas of greatest need and support the development of regional specific hypotheses for in-depth examination. The aim of this study was to describe the geographic variation in the IR-LLA across Australia and understand whether the effect of common risk factors was the same across regions. Using hospital episode data from the Australian National Hospital Morbidity database and Australian Bureau of Statistics, the all-cause crude and age-standardised IR-LLA in males and females were calculated for the nation and each state and territory. Generalised Linear Models were developed to understand which factors influenced geographic variation in the crude IR-LLA. While the crude and age-standardised IR-LLA in males and females were similar in most states and territories, they were higher in the Northern Territory. The effect of older age, being male and the presence of type 2 diabetes was associated with an increase of IR-LLA in most states and territories. In the Northern Territory, the younger age at amputation confounded the effect of sex and type 2 diabetes. There are likely to be many factors not included in this investigation, such as Indigenous status, that may explain part of the variation in the IR-LLA not captured in our models. Further research is needed to identify regional- and population- specific factors that could be modified to reduce the IR-LLA in all states and territories of Australia.

Amputations in patients with diabetic foot ulcer: a retrospective study from a single centre in the Northern Territory of Australia

“…The mean age at LEA in our study was 57 years, about 10 years younger than that reported in other developed countries . Indigenous patients were even younger at 52.9 years, compared to the Australian national average age at LEA of 62.9 years . This is in accordance with a previous study from Far North Queensland .…”

Major lower limb amputations in Far North Queensland

“…The rates of BKA in this study as a proportion of total MLLAs (62.7%) was comparable to other Australian cohorts, with Lim et al . reporting 58.6% and a study looking at 5 years’ worth of data from all Australian states reporting 57.3% . This study found that Indigenous patients were significantly more likely to undergo BKA as opposed to above knee amputation, and one hypothesis for this could be due to sepsis being a more common indication, necessitating immediate definitive intervention.…”

“…Lower limb amputations, particularly in the context of diabetes, have been used as an indicator internationally to compare different health systems performance . Both Australian and international reports have shown that there are geographical variations in the incidence of MLLAs within nations . The most comprehensive report looking at geographical variation within Australia suggested further research to be focused on smaller geographical regions to determine specific at‐risk populations for lower limb amputations …”

“…1,[5][6][7][8] Both Australian and international reports have shown that there are geographical variations in the incidence of MLLAs within nations. [9][10][11][12] The most comprehensive report looking at geographical variation within Australia suggested further research to be focused on smaller geographical regions to determine specific at-risk populations for lower limb amputations. 11 Cairns Hospital (CH) services a unique population as the only major referral hospital in Far North Queensland (FNQ), with a population density of 1.77 people/km 2 for the Cairns and Hinterland Hospital and Health Service.…”

“…[9][10][11][12] The most comprehensive report looking at geographical variation within Australia suggested further research to be focused on smaller geographical regions to determine specific at-risk populations for lower limb amputations. 11 Cairns Hospital (CH) services a unique population as the only major referral hospital in Far North Queensland (FNQ), with a population density of 1.77 people/km 2 for the Cairns and Hinterland Hospital and Health Service. 13 The Cairns and Hinterland region has 12.6% of residents identifying as Indigenous, and services the Torres and Cape Health Service with 64% of their population identifying as Indigenous.…”