In this study [1] , Ji et al. describe the implication of non-alcoholic fatty liver diseases (NAFLD) on clinical outcomes in patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. They observed 37.6% prevalence of nonalcoholic fatty liver disease (NAFLD), which is a high percentage with respect to the population included in the study. Indeed, the prevalence of NALFD in China ranges from 15% to 40% [2] , with a high variability between different regions. In northeastern China, where the study was conducted, the reported prevalence is 26.9% [3] . This higher prevalence of NAFLD could be explained by an over-diagnosis, mainly due to the use of indirect methods. In the absence of histological data, NAFLD was identified using the hepatic steatosis index (HSI) and/or abdominal ultrasound examination. It is not specified in how many patients either or rather both methods were used. HSI is affected by inflammatory activity and fibrosis and has poor performance in populations with moderate to severe steatosis [4, 5] . Nevertheless, cut-offs above that of 36 used by the Authors in this study showed the best sensitivity/specificity for NAFLD detection [4] . No information about other possible confounding factors was provided, the most common one being excessive alcohol intake (>=30 g for men and >=20 g for women) [6] . Nevertheless, human immunodeficiency virus (HIV) infection was reported among patients' comorbidities but was not considered in the analysis, representing a further confounding factor for both clinical outcomes and indirect diagnosis of NAFLD.
Besides these considerations, as also stated by the Authors, SARS-CoV-2 infection is frequently associated with the increase in transaminases and gamma-glutamyl transpeptidase (GGT) serum levels [7, 8] . This is the main bias, potentially leading to the increase in HSI with the consequent overestimation of the prevalence of NAFLD in this population of patients. Nevertheless, the association between NAFLD, increased risk of disease progression and longer viral shedding time could be explained by advanced age, higher BMI and prevalence of comorbidities (e.g. diabetes, arterial hypertension, cardiovascular disease) in the group of patients classified as "NAFLD". Indeed, the unfavorable clinical outcome of SARS-CoV-2 infection in more frail patients is wellknown all over the world [9, 10] .
Overall, the conclusions of this study should be taken with caution and only larger series that include patients with a previous diagnosis of NAFLD before SARS-CoV-2 infection will clarify the clinical outcome of the disease in these patients.