The study is based on data from morbidly obese patients who fulfilled the criteria for bariatric surgery during 2016-2018 at the Department of Surgery, University Hospital Ostrava, Czech Republic.

The study is based on data from morbidly obese patients who fulfilled the criteria for bariatric surgery during 2016-2018 at the Department of Surgery, University Hospital Ostrava, Czech Republic. Patients with age above 18 years, BMI > 35-40 kg/m2, and associated with at least one of the complications including hypertension, diabetes, and failure of the current therapies to relieve the symptoms were included in the study. Patients included in the current study do not have a history of excessive alcohol consumption, use of hepatotoxic drugs, infectious liver diseases (i.e. hepatitis A, B, C), and genetic hemochromatosis. A total of 72 patients including n = 26 during 2016, n = 26 during 2017, and n = 20 during 2018 who qualified for bariatric surgeries were included in this observational study. Data related to patients' gender, age (years), weight (kg), height (cm), and associated co-morbidities like diabetes and hypertension were recorded before surgery. BMI (kg/m2), biochemical parameters including triglycerides profile (mmol/L), platelet count (number/L), Gamma glutamyl-transferase (international units - IU/L), albumin concentration (g/L), Alanine amino-transferases (units/L), Aspartate aminotransferases (international units - IU/L), were evaluated following standard procedures. Platelet count, triglycerides, and enzymes were determined using standard procedures.

The biochemical results were compared to the corresponding paired values before surgery and after surgery. The current study was designed to prospectively investigate the effect of bariatric surgeries among non-alcoholic obese individuals from 2016-2018 and one year follow up on liver biochemistry, BMI, non-alcoholic fatty liver disease (NAFLD) fibrosis score, Fibrosis 4 (FIB 4) Index, and Fatty Liver Index (FLI).

The continuous variables were expressed as mean ± standard deviation and median (interquartile range) in case of normal and non-normal distribution, respectively. The Shapiro-Wilk test was used to test for normal distribution. The within-patient changes in clinical parameters (continuous or ordinal variables) from baseline to 1-year after bariatric surgery were compared using the Wilcoxon matched-pairs signed-rank tests for ordinal variables and continuous variables when the change was not normal or using the paired Student's t-test otherwise. The statistical testing was done at the two-tailed α level of 0.05. The data were analyzed using GraphPad Prism Version 8.0.2 (GraphPad Software, Inc., USA).

Inclusion Criteria:

• age 18 years and above
• BMI > 35-40 kg/m2
• hypertension or diabetes or failure of the current therapies to relive the symptoms

Exclusion Criteria:

• history of excessive alcohol consumption
• use of hepatotoxic drugs
• infectious liver diseases (i.e. hepatitis A, B, C)
• genetic hemochromatosis

Patients with age above 18 years, BMI > 35-40 kg/m2 and associated with at least one of the complications including hypertension, diabetes and failure of the current therapies to relive the symptoms were included in the study. Patients included in the current study does not have a history of excessive alcohol consumption, use of hepatotoxic drugs, infectious liver diseases (i.e. hepatitis A, B, C) and genetic hemochromatosis.

Individual participant data will be made available to other researchers upon request.