Trends in the incidence, treatment, and outcomes of acute lower extremity ischemia in the United States Medicare population

Objective: Acute lower extremity ischemia (ALI) is a common vascular surgery emergency associated with high rates of morbidity and mortality. The purpose of this study was to assess contemporary trends in the incidence of ALI, the methods of treatment, and the associated mortality and amputation rates in the U. S. Medicare population. Methods: This was an observational study using Medicare claims data between 1998 and 2009. Outcomes examined included trends in the incidence of ALI; trends in interventions for ALI; and trends in amputation, mortality, and amputation-free survival rates. Results: Between 1998 and 2009, the incidence of hospitalization for ALI decreased from 45.7 per 100,000 to 26.0 per 100,000 (P for trend <.001). The percentage of patients undergoing surgical intervention decreased from 57.1% to 51.6% (P for trend <.001), whereas the percentage of patients undergoing endovascular interventions increased from 15.0% to 33.1% (P for trend <.001). In-hospital mortality rates decreased from 12.0% to 9.0% (P for trend <.001), whereas 1-year mortality rates remained stable at 41.0% and 42.5% (P for trend not significant). In-hospital amputation rates remained stable at 8.1% and 6.4% (P for trend not significant), whereas 1-year amputation rates decreased from 14.8% to 11.0% (P for trend <.001). In-hospital amputation-free survival after hospitalization for ALI increased from 81.2% to 85.4% (P for trend <.001); however, 1-year amputation-free survival remained unchanged. Conclusions: Between 1998 and 2009, the incidence of ALI among the U. S. Medicare population declined significantly, and the percentage of patients treated with endovascular techniques markedly increased. During this time, 1-year amputation rates declined. Furthermore, although in-hospital mortality rates declined after presentation with ALI, 1-year mortality rates remained unchanged.