Prevalence and Risk Factors for Diabetic Lower Limb Amputation: A Clinic-Based Case Control Study

Abstract

Objective. The aim of the study was to evaluate the prevalence of and risk factors for lower limb amputation in a specialist foot clinic-based setting. Methods. A retrospective quantitative study was conducted, using clinical and biochemical profiles of diabetic foot patients attending the High Risk Foot Clinic at The Townsville Hospital, Australia, between January 1, 2011, and December 31, 2013. Results. The total study sample included 129 subjects, comprising 81 males and 48 females with M : F ratio of 1.7 : 1. Twenty-three subjects were Indigenous Australians, representing 17.8% of the study population. The average age of the cohort was 63.4 years ± 14.1 years [CI 90.98–65.89]. Lower limb amputation was identified as a common and significant outcome (n = 44), occurring in 34.1%, more commonly amongst the Indigenous Australians (56.5% versus 29.2%; p = 0.94, OR 0.94). Risk factors most closely associated with amputation included diabetic retinopathy (p = 0.00, OR 4.4), coronary artery bypass graft (CABG) surgery (p = 0.01, OR 4.1), Charcot's arthropathy (p = 0.01, OR 2.9), and Indigenous ethnicity (p = 0.01, OR 3.4). Although average serum creatinine, corrected calcium, and glycosylated haemoglobin A1c (Hba1c) levels were higher amongst amputees they were statistically insignificant. Conclusions. Lower limb amputation is a common outcome and linked to ethnicity and neurovascular diabetic complications amongst subjects with diabetic foot ulcer. Further research is needed to identify why risk of lower limb amputation seems to differ according to ethnicity.

Major lower limb amputations in Far North Queensland

“…In the same study, sepsis was documented as the indication for amputation more frequently in Indigenous patients, a finding mirrored in this contemporary cohort . These results are consistent with studies from two other states in Australia with a high proportion of Indigenous residents, as well as another hospital in North Queensland . Outside of Australia, ethnic differences in the rates of MLLA have been documented in multiple regions, including higher rates in African‐American and Hispanic men in America .…”

Chronic wounds in Australia: A systematic review of key epidemiological and clinical parameters

“…Several studies on DFUs reported on rates of DFU‐related amputation . The studies measured rates of ≥1 minor amputation (below the ankle), ranging from 2.1% to 36.5%, and rates of ≥1 major amputation (above the ankle), ranging from 0.5% to 23.0% .…”

Regional variation in the risk of lower‐limb amputation among patients with diabetes in New Zealand

“…In recent work, we showed that Māori patients are 65% more likely to undergo major lower‐limb amputation than European/Other patients, even after adjusting for sex, age, deprivation, rurality, comorbidity and prior amputation (adjusted hazard ratio (HR): 1.65, 95% CI 1.37–1.97) . These disparities have also been found in other settings: for example, higher amputation rates have been found among Indigenous patients with diabetes compared to their non‐Indigenous counterparts in areas including Australia . The factors driving the increased risk of major amputation among Māori are likely to be multifactorial, and include a complex web of increased morbidity (including peripheral vascular disease) and reduced access to health services and in particular high‐quality foot care services (including that available in the private health care system).…”

“…Older patients are more likely to undergo amputation than younger patients, and patients with substantial comorbidity in addition to their diabetes are at higher risk than those with little or no comorbidity . Men are more likely to undergo amputation than women, and Indigenous populations are at greater risk than non‐Indigenous populations . In NZ, Māori patients with diabetes are 65% more likely to undergo a major amputation compared to the European/other population …”