Contemporary National Incidence and Outcomes of Acute Limb Ischemia

Acute limb ischemia (ALI) is a morbid and deadly diagnosis. However, existing epidemiologic studies describing ALI predate the introduction of the Affordable Care Act in 2010 and direct oral anticoagulants in 2011. Thus, we synergized the National Inpatient Sample (NIS) and United States Census to define contemporary trends in the incidence, treatment, and outcomes of ALI in the US.

We included emergent admissions of adults with primary diagnosis of lower extremity ALI in survey-weighted NIS data (2005-2020). Mann-Kendal trend test evaluated ALI incidence (primary outcome), anticoagulation usage, insurance coverage, revascularization type, and in-hospital amputation/death. Multivariable logistic regression quantified covariate associations with in-hospital amputation/death.

Of the 582,322,862 estimated hospitalizations in the NIS, 227,440 met the inclusion criteria (mean age 68.80 years, 49.94% women, 76.66% White). ALI incidence peaked in 2006 (7.16/100,000 person-years) but has declined since 2015 to 4.16/100,000 person-years in 2020 (p_trend = 0.008). Endovascular revascularization, anticoagulation, and Medicaid coverage increased, while self-pay insurance decreased (p_trend < 0.05). Amputation rates significantly decreased from 8.04 to 6.54% (p_trend = 0.01) while death rate remained at 5.59% (p_trend = 0.16) over the study period. Prehospitalization anticoagulation was associated with decreased amputation (adjusted odds ratio [aOR] = 0.74 (95% confidence interval [CI] 0.65-0.84)) and death (aOR = 0.50 (95% CI 0.43-0.57)). When controlling for covariates, women had a higher risk of death (aOR = 1.17 (95% CI 1.07-1.27), P < 0.0001), while Black patients had a higher risk of amputation (aOR = 1.24 (95% CI 1.10-1.41), P < 0.0001).

Our US population based epidemiological study demonstrates that ALI incidence and in-hospital amputation rates are decreasing, while mortality remains unchanged. We further highlight the ongoing need for ALI investigation specifically as it relates to access to care, antithrombotic therapy use, treatment strategy, and strategies to combat gender and racial disparities.