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

Michael P Dillon,Muhammad Akram,Lauren V Fortington,Bircan Erbas,Friedbert Kohler,Wataru Nishimura

doi:10.1371/journal.pone.0170705

Michael P Dillon, Muhammad Akram + Show 4 more

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https://doi.org/10.1371/journal.pone.0170705

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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.

Highlights

In Australia, there are some 8000 lower limb amputations (LLA) performed annually [1,2]
One-third of LLA occurred in people between 35–60 years, with a small proportion of people younger than 35 years (Table 1)
While the crude and age-standardised incidence rate (IR)-LLA in males and females were similar in most states and territories, they were higher in the Northern Territory

Summary

Introduction

In Australia, there are some 8000 lower limb amputations (LLA) performed annually [1,2]. There are no studies that quantify whether the effect of common risk factors such as sex, age or the presence of diabetes are similar across different geographic regions. Economically-developed, countries has shown considerable geographic variation in the IR-LLA[6,7,8,9,10]. Synthesis of these investigations suggests that it is common for the IR-LLA to be two-three times higher in some regions compared to others. No studies have examined whether the effect of common risk factors is the same across geographic regions

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