Introduction
Nonalcoholic Fatty Liver Disease (NAFLD) is currently the most common chronic liver disease in the developed world where it has become a leading cause of cirrhosis, Hepatocellular carcinoma, and recourse to liver transplantation. It is highly associated with overweight and obesity. However, in Tunisia where obesity is recognized as a real public health problem, the prevalence of NAFLD, in this population, remains undetermined.
Aims & Methods
The aim of our study was to estimate the prevalence of NAFLD and the risk of advanced liver fibrosis in an obese population using Transient Elastography (Fibroscan), as well as to identify its main risk factors.
We conducted a prospective study, enrolling all patients followed for obesity in the department of Nutrition and Diabetology and referred to the department of Hepato-gastroenterology between January 2022 and July 2022, for non-invasive screening of hepatic steatosis. Controlled attenuated parameter (CAP) and liver stiffness measurement (LSM) were assessed by Fibroscan. The presence of hepatic steatosis was defined by CAP ≥ 248 dB/min. A high risk of advanced fibrosis was defined, based on EASL guidelines 2021, by LSM ≥ 12 kPa. The conditions for performing the examination, its reliability criteria, and its contraindications, as set by its manufacturer, were respected. Patients known to have pre-existing chronic liver disease, whatever its etiology, as well as chronic alcohol consumers or those with chronic medication other than that of a metabolic syndrome, were not included in this study.
For all patients diagnosed with hepatic steatosis, a specific check-up was systematically performed, in particular metabolic and virological, a measurement of ferritinemia and serum TSH levels. Statistical analysis of all data was performed using SPSS software (version 22) and P values < 0.05 were considered statistically significant.
Results
We enrolled 219 patients, 88.1% were women, with a mean age of 49 years [18-77 years], a mean body mass index (BMI) of 40.64 ± 10.08 kg/m2, and a mean waist circumference (WC) of 115.29 ± 17.51 cm.
The mean values of CAP and LSM were 291.41 ± 53.48 dB/m and 5.39 ±3.22 kPa, respectively. NAFLD was present in 76.9% of patients. Among them, 4.7% had a high risk of advanced fibrosis.
In univariate analysis, the presence of NAFLD was significantly associated with type 2 diabetes (T2D) (p=0.023), WC (p=0.033), total cholesterol level (p=0.016), triglyceride level (p=0.014), fasting blood glucose (p=0.004), while advanced fibrosis was significantly associated with T2D (p=0.031) and platelet count (p=0.014).
In multivariate analysis, only WC was independently associated with the presence of NAFLD (p=0.007). ROC curve analysis showed that WC had good specificity and sensitivity in predicting NAFLD (AUC=0.776 [0.634-0.918]) with a cut-off of 107.5. In contrast, no factor was independently associated with a high risk of advanced fibrosis.
Conclusion
More than 2/3 of obese people turned out to be affected by NAFLD in our Tunisian population, with more than 4% already having a completely unrecognized high risk of advanced fibrosis. This is an alarming result that should encourage us to implement a systematic screening for NAFLD in this population and in which case an evaluation of hepatic fibrosis in order to activate the management of obesity in its various aspects, which may go as far as to indicate metabolic surgery before it becomes contraindicated, particularly by advanced liver disease.