Resting Heart Rate as a Physiologic Marker of Steatosis in MASLD: NHANES 2017-2020 Analysis

Background and Objectives: Metabolic dysfunction-associated steatotic liver disease (MASLD) is closely linked to systemic cardiometabolic dysfunction. Resting heart rate (RHR), a marker of autonomic and metabolic stress, has been associated with metabolic syndrome and cardiovascular disease, though its relationship with MASLD remains incompletely characterized. We evaluated the association between RHR and liver-related outcomes in a nationally representative U.S. cohort. Materials and Methods: We analyzed adults aged 20-79 years from NHANES 2017-2020 with valid vibration-controlled transient elastography (VCTE) measurements. Participants with significant alcohol use, viral hepatitis, pregnancy, use of heart rate-modifying medications, or missing key data were excluded. Liver outcomes included elevated alanine aminotransferase (ALT), advanced steatosis (CAP ≥ 290 dB/m), FIB-4 fibrosis category, and VCTE-defined fibrosis. Multivariable regression models adjusted for demographic and metabolic covariates were used to evaluate associations between RHR and liver-related outcomes. Results: A total of 3532 adults were included. Each 1 beat-per-minute increase in RHR was independently associated with elevated ALT (OR 1.025, 95% CI 1.002-1.050, p = 0.043) and advanced steatosis (OR 1.036, 95% CI 1.001-1.073, p = 0.048). No significant association was observed between RHR and higher FIB-4 category (OR 1.025, 95% CI 0.992-1.060, p = 0.169) or VCTE-defined fibrosis (OR 0.990, 95% CI 0.961-1.021, p = 0.481). Associations with ALT and steatosis were attenuated after adjustment for glycemic and lipid parameters. Conclusions: Higher RHR was associated with steatosis-related and metabolic liver outcomes, but not fibrosis, in a nationally representative cohort. These findings suggest that RHR may reflect underlying autonomic and metabolic dysfunction relevant to early MASLD pathogenesis rather than advanced fibrotic disease.