Abstract 5788: The Incidence and Health Economic Burden of Critical Limb Ischemia and Ischemic Amputation in Minnesota: 2005–2007

Abstract

Background: Critical limb ischemia (CLI) is the most severe manifestation of peripheral artery disease (PAD) and is associated with high rates of morbidity and mortality, including subsequent myocardial infarction, stroke, and amputation. Nevertheless, the annual incidence of CLI in the United States is not known and there is no active national surveillance. Methods: We have estimated the incidence of ischemic amputation using all inpatient hospital discharge claims in Minnesota. These claims represent approximately 97% of hospitalizations in the state. Major and minor ischemic amputations were identified through ICD-9 procedure codes for lower limb amputation not due to trauma or cancer. This coding algorithm can be applied to other state-based hospitalization claims databases. Results: The age-adjusted incidence of ischemic amputation in 2007 was 18.8 (95% C.I. 17.7–19.9) per 100,000 (n=1,038). Amputations increased significantly with age and were more than twice as high in men as in women (25.1 vs. 11.3 per 100,000). The incidence of amputation did not differ significantly by rural or urban residence. Of these hospitalizations, 45% were for major above ankle leg amputations. The mean total charge for each hospitalization was $53,726, with cumulative charges for ischemic amputation hospitalizations of $56.2 million statewide in 2007. The incidence of ischemic amputation is significant as it represents approximately half of the annual stroke mortality rate (36.2 per 100,000 in 2007) with total charges approximately 20% of those for annual stroke hospitalizations. Applying this incidence and these charges for ischemic amputation in Minnesota to the entire US population in 2008 yields an estimate of more than 57,000 amputations and hospitalization costs of $3.1 billion. Conclusion: Ischemic amputation represents only the most severe CLI clinical event and underestimates the total burden of CLI and severe PAD. The incidence of ischemic amputation remains high, and results in major morbidity and health economic costs. These data permit the first population-based estimate of ischemic amputation in the USA in a non-selected population at risk.