In a recent issue, van der Poorten et al.1 reported an association of nonalcoholic steatohepatitis (NASH) with liver inflammation and fibrosis independent of insulin resistance and hepatic steatosis as assessed by magnetic resonance imaging. Although this association is already present, the study is important because it provides scientific information on this clinically relevant condition. However, we think that some points should be discussed.
First, as shown in Table 1, most of the patients with NASH are overweight or obese. In addition, an important portion of the study participants have other metabolic disturbances (high blood pressure, dyslipidemia, etc.) alone or in combination. It is well known that all components that constitute the metabolic syndrome (MetS) are risk factors for type 2 diabetes mellitus and also prediabetes, namely, impaired fasting glucose and/or impaired glucose intolerance.2 Although both T2DM and impaired glucose tolerance are among the components of MetS,3 plasma insulin and adipokine levels differ according to the degree of glucose dysregulation.4, 5 The same is also true for hypertension or elevated blood pressure and dyslipidemia.6, 7 Second, apart from the thiazolidinediones, no information about the drug use of the subjects could be seen in the text. We know that circulating adipokines and measures of insulin sensitivity are easily affected by medications started for the metabolic problems mentioned above.8, 9, 10
The authors state in their article that the participants were accepted as having MetS according to the Adult Treatment Panel III criteria. The diagnostic criteria can be used clinically with success; however, while designing clinical studies to display mechanistic associations, we have to give ultimate effort to exclude possible confounders that might interfere with the results. Therefore, we would like to ask the authors whether they can present some new results by categorizing the patients with NASH according to metabolic confounders such as type 2 diabetes mellitus, impaired glucose tolerance, blood pressure, and lipid profile. This may provide the readers clearer information related to the mechanism(s) of NASH.