Low ankle-brachial index is associated with higher cardiovascular mortality in individuals with nonalcoholic fatty liver disease

Background and aims Ankle brachial index (ABI) is a risk factor for cardiovascular mortality, but it is unclear whether ABI is associated with cardiovascular mortality in patients with nonalcoholic fatty liver disease (NAFLD). The current study aimed to evaluate the association between ABI with cardiovascular and all-cause mortality in patients with NAFLD. Methods We performed a cohort study using the data of the1999-2004 National Health and Nutrition Examination Survey data of adults. Mortality data were followed up to December 2015. NAFLD was defined by the hepatic steatosis index or the US fatty liver index. ABI was classified into three groups: ABI <= 0.9 (low value); 0.9 < ABI <= 1.1 (borderline value); ABI greater than 1.1 (normal value). Results We found that low ABI was associated with an increased risk of cardiovascular mortality in patients with NAFLD (HR: 2.42, 95% CI 1.10-5.33 for low value ABI vs normal value ABI, P for trend = 0.04), and the relationship was linearly and negatively correlated in the range of ABI < 1.4. However, low ABI was not associated with all-cause mortality in patients with NAFLD. Stratified by cardiovascular disease, ABI remains inversely correlated with cardiovascular mortality in NAFLD patients without cardiovascular disease. Stratified by diabetes, ABI is inversely correlated with cardiovascular mortality in NAFLD patients regardless of diabetes status. Conclusions Low ABI is independently associated with higher cardiovascular mortality in NAFLD cases. This correlation remains significant even in the absence of pre-existing cardiovascular disease or diabetes.