The Incidence and Health Economic Burden of Ischemic Amputation in Minnesota, 2005-2008

INTRODUCTION Critical limb ischemia (CLI) is the most severe manifestation of peripheral artery disease (PAD), is associated with high rates of myocardial infarction, stroke, and amputation, and has a high health economic cost. The objective of this study was to estimate the incidence of lower limb amputation, the most serious consequence of CLI, and to create a surveillance methodology for the incidence of ischemic amputation in Minnesota. METHODS We assessed the incidence of ischemic amputation using all inpatient hospital discharge claims in Minnesota from 2005 through 2008. We identified major and minor ischemic amputations via the International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) procedure codes for lower limb amputation not due to trauma or cancer and assessed geographic and demographic differences in the incidence of ischemic amputation. RESULTS The age-adjusted annual incidence of lower limb ischemic amputation in Minnesota during the 4-year period was 20.0 per 100,000 (95% confidence interval, 19.4-20.6). Amputations increased significantly with age, were more common in men and in people with diabetes, and were slightly more common in rural residents. The number of amputation-related hospitalizations was steady over 4 years. The median total charge for each amputation was $32,129, and cumulative inpatient hospitalization charges were $56.5 million in 2008. CONCLUSION The incidence of ischemic amputation is high and results in major illness and health economic costs. These data represent the first population-based estimate of ischemic amputation at the state level and provide a national model for state-based surveillance.