Liver disease is a significant risk factor for cardiovascular outcomes - a UK Biobank study

Background: Chronic liver disease (CLD) and cardiovascular diseases (CVD) share common risk factors; the former is associated with a two-fold greater incidence of CVD. With most CLD being preventable/modifiable, early identification of at high-risk individuals is crucial. Using data from the UK Biobank imaging sub-study, we tested the hypothesis that early signs of liver disease (measured by iron corrected T1-mapping (cT1)) is associated with an increased risk of major cardiovascular events. Methods: Liver disease activity (cT1) and fat (PDFF) were measured using LiverMultiScan from images acquired between January-2016 and February-2020 in the UK Biobank imaging sub-study. Multivariable Cox regression was used to explore associations between liver cT1 (MRI) and primary CVD outcomes (coronary artery disease, atrial fibrillation, embolism/vascular events, heart failure and stroke), as well as CVD hospitalisation and all-cause mortality. Other liver blood biomarkers (AST, ALT, AST/ALT ratio, FIB4), general metabolism biomarkers (CRP, HbA1c, systolic blood pressure (SBP), total cholesterol), and demographics were also included. Subgroup analysis was conducted in those without metabolic syndrome (MetS= at least 3 of these traits: a large waist, high triglycerides, low HDL cholesterol, increased SBP, or elevated HbA1c) Results: 33,616 participants in the UK Biobank imaging sub-study (65 years, mean BMI 26kg/m2, mean HbA1c 35mmol/mol) had complete MRI liver data with linked clinical outcomes [median time to major CVD event onset: 1.4 years (range:0.002-5.1); follow-up: 2.5 years (range:1.1-5.2)]. Liver disease activity (cT1), but not liver fat (PDFF), was associated with a higher risk of any major CVD event [HR(CI) 1.14(1.03-1.26), p=0.008], AF [1.30 (1.12-1.5), p<0.001]; HF [1.30 (1.08 - 1.58), p=0.004]; CVD hospitalisation [1.27(1.18-1.387, p<0.001] and all-cause mortality [1.19(1.02-1.38), p=0.026]. FIB4 index, was associated with HF [1.06 (1.01 - 1.10)), p=0.007]. The risk of CVD hospitalisation was also independently associated with cT1 in individuals without MetS [1.26(1.13-1.4), p<0.001]. Conclusion: Liver disease activity, as measured with MRI-derived biomarker cT1, was independently associated with a higher risk of new onset CVD events and all-cause mortality. This association occurred even without pre-existing impairment of metabolic health and was independent of FIB4 or liver fat content. cT1 was identified as a major predictor of adverse CVD outcomes.