Long-term mortality after lower-limb amputation

Abstract

Background: Mortality after amputation is known to be extremely high and is associated with a number of patient features. We wished to calculate this mortality after first-time lower-limb amputation and investigate whether any population or treatment factors are associated with worse mortality.

Objective: To follow up individuals after lower limb amputation and ascertain the mortality rate as well as population or treatment features associated with mortality.

Study design: A prospective cohort study.

Methods: Prospective lower-limb amputations over 1 year (N = 105) at a Regional Rehabilitation Centre were followed up for 3 years.

Results: After 3 years, 35 individuals in the cohort had died, representing a mortality of 33%. On initial univariate analysis, those who died were more likely to have diabetes mellitus (χ(2) = 7.16, df = 1, p = 0.007) and less likely to have been fitted with a prosthesis (χ(2) = 5.84, df = 1, p = 0.016). There was no association with age, gender, level of amputation, social isolation, significant medical co-morbidity other than diabetes or presence of mood disorders. A multi-variable logistic regression (backward step) confirmed that diabetes (odds ratio = 3.04, confidence intervals = 1.25-7.40, p = 0.014) and absence of prosthesis-fitting (odds ratio = 2.60, confidence interval = 1.16-6.25, p = 0.028) were independent predictors of mortality.

Conclusion: Mortality after amputation is extremely high and is increased in individuals with diabetes or in those who are not fitted with a prosthesis after amputation.

Clinical relevance: The link between diabetes and mortality after amputation has been noted by others, but this is the first study to find an effect from prosthetic limb-wearing. This requires further investigation to ascertain why the wearing of a prosthetic limb, confers an independent survival benefit that is not related to the presence of medical co-morbidity.

Keywords: Amputation; diabetes mellitus; lower limb; outcome studies; prosthesis.