Letter to the Editor: Metabolic dysfunction‐associated fatty liver disease and excessive alcohol consumption are both independent risk factors for mortality

To the editor, We read the study by van Kleef et al.,1 which investigated the mortality risk of patients with metabolic‐associated fatty liver disease (MAFLD) in relation to alcohol use. The authors concluded that MAFLD increased mortality risk independent of excessive alcohol consumption. However, we have some concerns about this conclusion. First, a previous study has investigated the association between MAFLD and all‐cause mortality.2 They included 7761 individuals who fasted for >8 h, whereas 13,225 participants with available alcohol and liver ultrasound data were included in this study. The current study cohort had higher prevalence of MAFLD (34.7% vs. 25.9%) at baseline than the previously reported study. Considering that diabetes was an important diagnostic parameter defined by fasting glucose levels, we believe that the inclusion of an 8‐h fasting blood glucose level adds further credibility to the results and conclusions.3 Second, it is known that National Health and Nutrition Examination Survey recommends sampling weights to represent a nationally representative sample of the US population. Regretfully, any sampling weights were not used in the presented data. Of note, inverse probability treatment weighting (IPTW) is an efficient and reliable approach to address imbalances. Because the authors chose IPTW to minimize the potential bias in this study, details were not shown before and after IPTW, such as the baseline table and the Cox regression analysis. Thus, more details are suggested. Third, some important metabolic cofactors were not adjusted in multivariate analysis, such as diabetes, hypertension, and cholesterol levels. Metabolic factors were important confounders in the study of MAFLD, which also needed to be adjusted in the multivariable adjusted analysis.2 However, as shown in Tables 3 and 4 of van Kleef et al., metabolic factors were not adjusted in the multivariable adjusted analysis. Therefore, the findings that MAFLD and excessive alcohol were independent and simultaneous predictors for all‐cause mortality might be inadequate. Our confusion is regarding whether their prognosis in MAFLD−Alc+ group was not determined by simply alcohol consumption but rather by alcohol‐related metabolic disorders leading to health concerns.4 For this reason, we recommend that confounders of metabolic factors should be considered in this study. In summary, consideration about the mentioned questions may help solidify the conclusions of this study.