A Meta-analysis of Long-term Mortality and Associated Risk Factors following Lower Extremity Amputation

Background: A majority of patients undergoing lower limb amputations have diabetes or peripheral artery disease. Despite improvements in care, there remains a substantial perioperative mortality associated with these procedures. Less well-defined is the mortality risk to these patients going forward, once outside the perioperative period. The aim of this systematic review is to summarize and pool the available data to determine the long-term mortality associated with amputation in the diabetic and peripheral vascular patient, as well as to define specific factors associated with increased mortality risk. Methods: Four databases were searched from January 2005 through July 2015 using the Medical Subject Headings terms amputation, lower extremity, and mortality. Inclusion criteria were observational and cohort studies where >= 50% of amputations were attributable to diabetic or vascular etiologies. Final article inclusion was approved by reviewer consensus. Bias was assessed with the Joanna Briggs Institute Critical Appraisal Tool for cohort studies. Results: Of the 365 unique records screened, 43 abstracts and 21 full articles were reviewed and 16 studies ultimately included. The overall mortality rate was 47.9%, 61.3%, 70.6%, and 62.2% at 1-, 2-, 3- and 5-year follow-up, respectively. In addition to diabetes and peripheral vascular disease, comorbid factors associated with at least a 2-fold increased mortality were coronary artery disease, cerebrovascular disease, renal dysfunction, American Society of Anesthesiologists class >= 4, dementia, and nonambulatory status. Surgical factors, including higher amputation level and need for staged surgery with up-front guillotine amputation, were also correlated with increased mortality. Conclusions: The overall mortality rate after primary lower limb amputation in the diabetic and peripheral vascular population is substantial, and should not be underestimated when making decisions regarding limb salvage. Similar to patients undergoing revascularization, comorbid conditions associated with higher mortality should be optimized before surgery whenever possible.