Trends in Surgical Indications for Major Lower Limb Amputation in the USA from 2000 to 2016.

OBJECTIVE: Major lower limb amputation is an important cause of morbidity and mortality in the USA. Little is known about the prevalence of the various indications for amputation, or if these indications have changed over time. The purpose of this study was to assess the indications for major amputation over a 17 year period and to determine whether surgical indications have shifted over this time period.

METHODS: A retrospective, population based analysis of patients undergoing major amputation between 2000 and 2016 was performed using the National Inpatient Sample. Surgical indications for major amputation were classified as chronic ischaemia, acute limb ischaemia (ALI), infection, oncological, trauma, other, or any combination of these indications. Prevalence rates of surgical indications were calculated using logistic regression. Prevalence differences across years were assessed using likelihood ratio tests to determine statistical significance.

RESULTS: Of 1 002 119 weighted hospitalisations for patients undergoing major amputation during the study period, the majority had chronic ischaemia (72%) or infection (15%) as the primary indication for amputation. Patients were predominantly male (60%) and diabetic (61%). Renal insufficiency was the only measured comorbidity that changed significantly over time (from 6% to 39%), although changes in coding procedures are partially responsible for the increase. From 2000 to 2016, the proportion of amputations done for chronic ischaemia alone decreased from 60% to 40% (p < .001), while the proportion of amputations that included infection in the presence of chronic ischaemia nearly doubled from 20% to 40% (p < .001). Major amputation due to ALI, oncology, or trauma was stable across the study period.

CONCLUSION: Surgical indications for major amputation have changed between 2000 and 2016. Infection related amputations increased significantly during the study period. Further evaluation and modification of treatment protocols for limb infection are crucial to decreasing infection related major limb amputation.