Association Between Metabolic Dysfunction-Associated Steatotic Liver Disease and Risk of Aortic Aneurysm and Dissection: A Nationwide Cohort Study.

Background/Objectives: Prior studies linking fatty liver-related phenotypes to aortic disease have mainly focused on abdominal aortic aneurysm and used earlier nomenclature. We examined associations of metabolic dysfunction-associated steatotic liver disease (MASLD) and cardiometabolic risk factor (CMRF) count with aortic aneurysm and aortic dissection. Methods: We analyzed 240,074 adults from the 2009-2010 Korean National Health Insurance Service health-screening database after exclusions. Steatotic liver disease was assessed using the Fatty Liver Index, and MASLD was defined as steatotic liver disease with at least one CMRF. Outcomes were identified using claims-based International Classification of Diseases, 10th Revision codes. Adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox models. Results: Over a median follow-up of 9.6 years, 1018 aortic aneurysm events and 285 aortic dissection events were recorded. Incidence rates in the MASLD and reference groups were 0.54 versus 0.21 for aortic aneurysm and 0.15 versus 0.04 for aortic dissection per 1000 person-years. Compared with individuals without steatotic liver disease and without CMRFs, MASLD was associated with higher risks of aortic aneurysm (adjusted HR, 1.58; 95% CI, 1.14-2.18) and aortic dissection (adjusted HR, 2.12; 95% CI, 1.03-4.38). Compared with individuals without steatotic liver disease but with CMRFs, MASLD remained associated with aortic aneurysm, but not aortic dissection. Higher CMRF count was associated with aortic aneurysm. Conclusions: MASLD and higher CMRF count were associated with incident aortic aneurysm, whereas findings for aortic dissection were less consistent. Further studies with more precise liver and aortic phenotyping are warranted.