PARIS — Although metabolic liver diseases are mainly seen in patients with obesity or type 2 diabetes, studies have shown that non-alcoholic fatty liver disease, recently renamed metabolic dysfunction-associated steatotic liver disease (MASLD), also affects slim patients. Moreover, the condition could be particularly severe in this population.
A recent study carried out using data from the French Constance cohort showed that of the 25,753 patients with MASLD, 16.3% were lean (BMI of less than 25 kg/m²). In addition, 50% of these patients had no metabolic risk factors.
These slim patients with MASLD were most often young patients, for the most part female, and less likely to present with symptoms of metabolic syndrome. Asian patients were overrepresented in this group.
“These patients probably have genetic and/or environmental risk factors,” commented senior author Lawrence Serfaty, MD, PhD, head of the metabolic liver unit at the new Strasbourg public hospital, during a press conference at the Paris NASH meeting.
The disease was more severe in slim subjects. Overall, 3.6% of the slim subjects had advanced fibrosis (Forns index > 6.9) vs 1.7% of patients with overweight or obesity (P < .001), regardless of demographic variables, metabolic risk factors, and lifestyle. They also had higher alanine aminotransferase levels.
In addition, over the course of a mean follow-up of 3.8 years, liver events (eg, cirrhosis, decompensated cirrhosis, and liver cancer), chronic kidney diseases, and all-cause mortality were much more common in these patients than in patients with overweight or obesity (adjusted hazard ratios of 5.84, 2.49, and 3.01, respectively). It should be noted that these clinical results were linked to fibrosis severity in both slim and overweight subjects with MASLD.
Nonetheless, cardiovascular events remained more common in patients with overweight or obesity, suggesting that obesity itself is a major risk factor for cardiovascular diseases, regardless of MASLD.
“Armed with these results, which confirm those obtained from other studies, we must seek to understand the pathogenesis of the disease in slim patients and study the role of the microbiota, genetics, and diet, as well as determining the effects of alcohol and tobacco, consumption of which was slightly more common in this subpopulation,” said Dr. Serfaty.
According to the study authors, sarcopenia and bile acids could also be involved in the pathogenesis of MASLD in slim patients. The researchers concluded that “due to the relatively low rate of MASLD in slim subjects, screening should target patients presenting with metabolic anomalies and/or unexplained cytolysis.”
This article was translated from the Medscape French edition.