Arun J. Sanyal
Fatty liver experts discussed the necessity of revising current common nomenclature of nonalcoholic fatty liver disease and alcoholic fatty liver disease to better reflect clinical phenotype based on growing prevalence and overlapping features of both classifications.
“With the increased global prevalence of fatty liver disease, efforts are underway to further characterize and sub-phenotype the disease as a necessary tool for the design of clinical trials and for patient stratification,” Arun J. Sanyal, MD, from the Virginia Commonwealth University, and colleagues wrote. “Until evidence points to a specific diagnostic test rather than merely exclusion criteria for diagnosis, we are calling for a consensus to develop a more appropriate nomenclature.”
According to Sanyal and colleagues, the current definition of NAFLD and distinction from ALFD is based solely on amount of alcohol consumption without specific mention to metabolic dysfunction.
A common threshold of alcohol use that rules out NAFLD is consumption of 30 g daily for men and 20 g daily for women, whereas light (1-9.9 g per day) to moderate (10-29.9 g per day) consumption in patients with NAFLD is not uncommon.
The authors noted that there has been a longstanding controversy on the impact of moderate alcohol consumption on NAFLD prognosis as some studies suggested a protective effect while others reported increased risks. More recent studies including one that comprised 649,000 cases with outcomes and another that followed 6,732 patients for an average of 11 years provide “convincing evidence that there is no safe limit for alcohol consumption” regarding liver health.
This negative impact also extends to NASH resolution based on a recent longitudinal study of patients with NAFLD who underwent paired biopsies. Low to moderate consumption correlated with less improvement in steatosis and NASH compared with no alcohol intake. Conversely, obesity and metabolic syndrome can aggravate progression of AFLD.
“Based on current evidence, one could argue that the conventional threshold of alcohol consumption for a diagnosis of NAFLD should be updated to zero or near to zero. In reality, this would be impractical due to a multitude of reasons,” they wrote, such as a lack of questionnaires that can exclude alcohol consumption to zero or near so.
Sanyal and colleagues suggested that a consensus should be to develop terminology that reflects pure “metabolic dysfunction predominant fatty liver” (or MPFL) and alcohol predominant fatty liver (or APFL), as most patients with liver disease will have overlapping contributions from both metabolic dysfunction and from alcohol.
“This we suggest is more than an issue of semantics and nomenclature since without more precise use of terms to define fatty liver diseases, neither science nor patient care can be optimal,” they wrote. “To improve consistency for future research, assessment of drugs in clinical trials, and public health initiatives, coordinated action by consensus is required, which is not solely for the academic purist.” – by Talitha Bennett
Disclosure: The authors report no relevant financial disclosures.