Association of Factor V Leiden and Ischemic Stroke in Young Adults: A National Inpatient Sample Analysis

Background The association between Factor V Leiden (FVL) and ischemic stroke in young adults remains uncertain. We evaluated inpatient FVL prevalence and hospital outcomes among young adults with ischemic stroke in the United States. Methods Using the 2016–2022 National Inpatient Sample, we identified hospitalizations for patients aged 18–49 years with a primary diagnosis of ischemic stroke and a secondary diagnosis of FVL. FVL prevalence in stroke hospitalizations was compared with non-stroke hospitalizations. Among stroke hospitalizations, we examined discharge disposition, length of stay, and inflation-adjusted costs using survey-weighted models adjusted for demographics and comorbidities. Results Among 67.8 million hospitalizations of adults aged 18–49 years, 297,905 (0.44%) were for ischemic stroke. FVL prevalence was higher in stroke than non-stroke hospitalizations (0.85% vs 0.25%, p < 0.001) and rose modestly over time in stroke admissions (0.81% in 2016 to 0.95% in 2022). Stroke patients with FVL were younger, more often female and White, and had fewer traditional vascular risk factors. After adjustment, FVL was associated with longer length of stay (14.3% increase) and higher costs (16.5% increase), with greater effects in males and Black and Hispanic patients; discharge disposition was similar by FVL status. Conclusions FVL is more prevalent among young adults hospitalized with ischemic stroke, who did not have traditional stroke risk factors. These findings support a possible hypercoagulable mechanism in a subset of ischemic stroke patients and highlight the need for prospective studies to guide targeted screening and primary prevention strategies.