Impact of the MetALD terminology on the prevalence of alcohol‐related fatty liver disease in US adults (2017–2020)

We read with interest the article published in the Liver International by Ciardullo et al.1 about the impact of MASLD and MetALD on clinical outcomes. Fatty liver disease caused by metabolic dysfunction is a leading cause of chronic liver disease; however, alcoholic liver disease (ALD) also contributes significantly to the burden of liver disease, despite receiving less attention.2 A newly proposed term, MetALD, describes the coexistence of metabolic dysfunction-associated steatotic liver disease (MASLD) and excessive alcohol intake.3 Nevertheless, there is a paucity of information regarding the impact of the MetALD concept on the overall prevalence of ALD. To investigate the prevalence of MetALD, data from the National Health and Nutrition Examination Survey (NHANES) 2017 to March 2020 cohort were analysed (Figure 1). The initial cohort consisted of 15 560 individuals; however, 5952 individuals were excluded due to being younger than 18 years of age or having missing gender data. Consequently, 9608 individuals were included in the analysis. Harmful alcohol consumption was defined as more than three drinks per day in males and more than two drinks per day in females throughout the past 12 months. Based on this criterion, 1440 (15%) individuals were identified as engaging in harmful alcohol consumption. The diagnosis of hepatic steatosis and fibrosis was established using the median values of the controlled attenuation parameter and liver stiffness measurement (LSM), with a threshold of 274 dB/m employed to determine the presence of steatosis. The prevalence of alcohol-related steatosis was approximately 6.2% in a cohort that was predominantly White (63.1%) and male (61.4%), with a mean age of 44.2 ± 14.9 years, a mean body mass index (BMI) of 34.5 ± 7.4 kg/m2, a mean alcohol intake of 154.5 ± 215.2 grams per week and a mean LSM of 6.9 ± 5.9 kPa. Upon applying the MetALD concept to this ALD cohort, a striking 98.4% of subjects with alcohol-related steatosis were reclassified as MetALD, with only 1.6% of subjects remaining classified as ALD. Among the subjects with MetALD, 97.4% met the BMI/waist circumference criterion, 58.2% had pre-diabetes or diabetes and 26.8% had hypertension. The interaction between alcohol intake and metabolic dysfunction is multifaceted. Two distinct definitions of fatty liver disease associated with metabolic dysfunction have emerged to address this complexity: metabolic dysfunction-associated fatty liver disease (MAFLD) and MASLD.4-6 The SLD definition proposes the term 'MetALD' to describe patients with MASLD who also exhibit excessive alcohol intake, without providing specific terms for MASLD coexisting with other causes. In contrast, the MAFLD definition eschews the introduction of new terms and instead incorporates the concept of dual aetiologies, encompassing the coexistence of MAFLD with any other cause, including excessive alcohol intake. To illustrate this concept, an analogy can be drawn from other metabolic disorders. Specifically, patients with dual metabolic dysfunction diseases (e.g. diabetes and hypertension) are typically diagnosed with both conditions simultaneously, rather than being assigned a distinct, combined term. Notably, the recent viewpoint by Moreno et al.7 representing the EASL Consortium for the Study of Alcohol-related Liver disease in Europe, raised significant concerns about the potential consequences of introducing new terminology such as 'MetALD' to describe patients with both metabolic dysfunction and excessive alcohol intake. Their primary apprehension was that this approach could inadvertently create a dichotomy among individuals exposed to alcohol, potentially leading to the exclusion of patients meeting metabolic criteria from being recognized as having ALD.7 Our analysis substantiates these concerns and suggests that adopting the concept of dual aetiology, rather than introducing new terminology, may be the more appropriate approach. In conclusion, the application of the MetALD concept to large US cohorts yielded a striking outcome: a significant 98.4% of subjects with alcohol-related steatosis were reclassified as MetALD, leaving a mere 1.6% of subjects classified as ALD. This finding raises important questions about the validity and utility of the MetALD concept, suggesting that it may require reevaluation and refinement to better capture the complexities of liver disease aetiology. All authors shared conceptualization and designed the idea in addition to collection of data. Yasser Fouad wrote the initial draft. All authors revised the manuscript and approved the final version. No funding was obtained or required for this study. All authors have nothing to disclose relevant to this work. Data sharing is not applicable to this article as no data sets were generated or analysed during the current study.