Interest of APA in Fatty Liver Disease Evaluation of Efficacy and Adherence to an Adapted Physical Activity (APA) Program in Patients With Metabolic Fatty Liver Disease

Non-Alcoholic Fatty Liver Disease (NAFLD) affects nearly 25% of the world's population and can lead to cirrhosis and hepatocellular carcinoma . Exercise alone in patients with NAFLD has been shown to improve hepatic steatosis. Since 2017, adapted physical activity (APA) has been a medical prescription by the referring physician in France. APA is thus expected to be a new treatment modality that will become central to the prevention and treatment of NAFLD. The reference examination for the non-invasive quantification of liver steatosis was the Spectro Magnetic Resonance Imaging (MRI) however this technique is expensive and until now reserved for research in highly specialized centers. More recently, the analysis of the MRI signal by a magnetic resonance imaging-derived proton density fat fraction (MRI-PDFF) sequence acquired during the performance of a classical MRI scan has been validated as a new, reliable technique that is easier to use routinely than Spectro MRI. However, different technical variants currently not standardized for the quantification of steatosis by PDFF MRI exist. MRI is not widely available and must be performed in a competent and expert center. In contrast, the quantification of steatosis by ultrasound using the classical "Controlled Attenuation Parameter" (CAP®) is available thanks to a FibroScan, which is widely distributed over France. Even if the quantification of steatosis is better by PDFF MRI than by the classical CAP®, the quantification of steatosis by the classical CAP® is well correlated with the hepatic histology. In addition, several studies have found a decrease in classical CAP® when applying non-drug or drug therapies to lose weight and/or improve insulin resistance in patients with NAFLD. Very recently, Echosens has developed a new technique -the continuous CAP- to improve the reliability of the classical CAP® in the evaluation of steatosis \[Audiere et al. ILC 2020\]. Continuous CAP® is no longer based on 10 but on 200 measurements of hepatic steatosis. This new measurement technique reduces the variability of the measurement of liver steatosis quantification by 42%. The aim of this work is to evaluate the decrease in hepatic steatosis by continuous CAP® and parameters evaluating non-invasively inflammation and hepatic fibrosis in patients with NAFLD subjected to the application of personalized dietary measures without or with the performance of personalized and reproducible physical activity via the prescription of an adapted physical activity. The evaluation will be carried out initially, at the end of the APA program and 24 weeks after the end of the APA program in order to look for a persistent effect of the modification in lifestyle.