Twenty-Year Analysis of Trends in the Incidence and In-Hospital Mortality for Lower-Extremity Arterial Thromboembolism

Abstract

Background— Epidemiology data for lower-extremity arterial thromboembolism (LET) are limited and may result from either acute limb ischemia or an acute exacerbation of critical limb ischemia. Given marked changes in both diagnosis and therapy over the last 2 decades, we hypothesized that this time period would have witnessed reductions in both the incidence and in-hospital mortality of LET. Methods and Results— Data from 1988 through 2007 from the National Hospital Discharge Survey were analyzed. All admissions for patients with LET were extracted, and the respective International Classification of Diseases, Ninth Revision, Clinical Modification codes were internally validated for both LET and acute limb ischemia. Descriptive statistics were used. The validity of the codes was good for identifying LET cases but poor for identifying acute limb ischemia cases because many of these acute presentations were attributable to critical limb ischemia. Over the 20-year span, there were 1.76 million cases of LET. The incidence of LET decreased significantly from 42.4 per 100 000 persons between 1988 and 1997 to 23.3 per 100 000 persons between 1998 and 2007. The in-hospital mortality for LET decreased significantly from 8.28% between 1988 and 1997 to 6.34% between 1998 and 2007, and male patients achieved greater mortality reduction compared with female patients. Treatments for acute limb ischemia showed decreasing use of surgical bypass and amputation and increasing rates of catheter-based thrombolysis. Conclusions— Over the 20-year study period, there have been significant reductions in both LET incidence and in-hospital mortality. Unfortunately, LET admissions extracted from an administrative database comprise a diverse group of individuals, including those with acute and chronic forms of limb ischemia and iatrogenic arterial injury, limiting the true assessment of ALI incidence.