Although the presence of fatty liver disease is not associated with prevalent or incidental atrial fibrillation (AF), higher liver stiffness, particularly among individuals without steatosis, is linked to prevalent AF. These findings were published in the Journal of Hepatology.

An analysis was embedded in the large prospective, population-based ongoing Rotterdam Study. The analysis included participants from the Rotterdam Study who had attended the abdominal ultrasound program from March 2009 to June 2014. Steatosis was evaluated with the use of ultrasound, liver stiffness was assessed via transient elastography, and AF was evaluated with the use of 12-lead electrocardiograms. Those individuals with no data available on AF or with more than 20% missing data for the variables included were excluded from the study.

Per guidelines from the European Association for the Study of the Liver, nonalcoholic fatty liver disease (NAFLD) was defined as “hepatic steatosis in the absence of secondary causes of steatosis comprising viral hepatitis (B or C), steatogenic drug use, and excessive alcohol consumption” of 20 grams or more for women and 30 grams or more for men. Participants were excluded from being considered as having NAFLD if quantitative alcohol data were missing when alcohol consumption frequency of 4 days or more weekly was reported, since excessive alcohol intake could not be ruled out.


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Liver stiffness was measured with the same device throughout the study period. If liver stiffness was greater than 7.0 kPa, 10 or more individual measurements were needed for a valid measurement with an interquartile range of 30% or less. High liver stiffness was defined as a valid liver stiffness measurement of 8.0 or more kPa.

A total of 5967 individuals underwent abdominal ultrasound, with 22 of them excluded for having no AF data available and 120 excluded for having missing data across more than 20% of the variables of interest. Thus, a total of 5825 participants were ultimately available for the analysis. Overall, 42.9%  of the patients are men. Mean age of the participants is 69.5±9.1 years and their mean BMI is 27.5.

At baseline, steatosis was observed in 2079 of the participants and AF in 405 of the individuals. Among those included in the analysis, 4270 have a valid measurement of liver stiffness and 262 demonstrate liver stiffness of 8.0 or more kPa.

Results of the study show that the presence of hepatic steatosis is not associated with a higher prevalence of AF across all multivariable models (odds ratio [OR] in fully adjusted models, 0.80; 95% CI, 0.62-1.03; P =.082). The findings are consistent for NAFLD and metabolic dysfunction–associated fatty liver disease.

Liver stiffness of 8.0 or more kPa, in contrast, is significantly associated with AF in fully adjusted models that include covariates affecting liver stiffness (OR, 2.08; 95% CI, 1.33-3.25; P =.001). A similar association is seen for continuous liver stiffness in multivariable analysis (OR, 1.09 per kPa; 95% CI, 1.03-1.16; P =.002); however, this is persistent only among those without steatosis (OR, 1.18 per kPa; 95% CI, 1.08-1.29; P< .001).

No significant associations are observed between steatosis (hazard ratio, 0.88; 95% CI, 0.59-1.33; follow-up, 2.1 years [range, 1.1-3.2]; P =.548) and incident AF.

Several limitations of the study include the study population having a mean age of 69.5 years and being almost entirely of European ancestry. Further, the results derived from the cross-sectional analysis could not be used to investigate causality.

Researchers concluded that the association of liver stiffness with AF might be “driven by venous congestion instead of fibrogenesis, but this awaits further validation.” An evaluation of cardiovascular health among individuals with high liver stiffness, particularly in the absence of overt liver disease, is recommended.

Disclosure: One of the study authors has declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of the author’s disclosures. 

Reference  

van Kleef LA, Lu Z, Ikram MA, de Groot NMS, Kavousi M, de Knegt RJ. Liver stiffness, but not fatty liver disease, is associated with atrial fibrillation: the Rotterdam Study. J Hepatol. Published online June 7, 2022. doi:10.1016/j.jhep.2022.05.030