High mortality risks after major lower extremity amputation in Medicare patients with peripheral artery disease

Background Little is known regarding the contemporary outcomes of older patients with peripheral artery disease (PAD) undergoing major lower extremity (LE) amputation in the United States. We sought to characterize clinical outcomes and factors associated with outcomes after LE amputation in patients with PAD. Methods Using data from the Centers for Medicare and Medicaid Services from January 1, 2000, to December 31, 2008, we examined the national patterns of mortality after major LE amputation among patients 65 years or older with PAD. Cox proportional hazards models were used to investigate the association between clinical variables, comorbid conditions, year of index amputation, geographic variation, and major LE amputation. Results Among 186,338 older patients with identified PAD who underwent major LE amputation, the mortality rate was 13.5% at 30 days, 48.3% at 1 year, and 70.9% at 3 years. Age per 5-year increase (hazard ratio [HR] 1.29, 95% CI 1.29-1.29), history of heart failure (HR 1.71, 95% CI 1.71-1.72), renal disease (HR 1.84. 95% CI 1.83-1.85), cancer (HR 1.71, 95% CI 1.70-1.72), and chronic obstructive pulmonary disease (HR 1.33, 95% CI, 1.32-1.33) were all independently associated with death after major LE amputation. Subjects who underwent above knee amputation had a statistically higher hazard of death when compared with subjects who underwent LE amputation at more distal locations (HR with above the knee amputation 1.31, 95% CI 1.25-1.36). Conclusions Older patients with PAD undergoing major LE amputation still face a slightly high mortality risk, with almost half of all patients with PAD dying within a year of major LE amputation.