Changes in Hepatic Steatosis and Fibrosis Indices in Patients with Morbid Obesity and Type 2 Diabetes Mellitus After Bariatric Surgery

BACKGROUND: The course of metabolic dysfunction-associated steatotic liver disease after bariatric surgery remains a critical clinical problem.

AIM: To evaluate changes in noninvasive indices of hepatic steatosis and fibrosis in patients with morbid obesity and type 2 diabetes mellitus 1 year after bariatric surgery.

METHODS: This study included 85 patients who underwent bariatric surgery at the Institute of Clinical and Experimental Lymphology between 2019 and 2024: mini-gastric bypass (n = 60) or sleeve gastrectomy with single-anastomosis ileal bypass (n = 25). Glycated hemoglobin (HbA₁c), triglyceride, low-density lipoprotein cholesterol, C-reactive protein, alanine aminotransferase, aspartate aminotransferase, γ-glutamyltransferase, and alkaline phosphatase levels were assessed before surgery and 1 year postoperatively. Moreover, noninvasive hepatic steatosis indices, namely, Fatty Liver Index (FLI), Hepatic Steatosis Index (HSI), Lipid Accumulation Product (LAP), and St-index, were evaluated. Fibrosis indices included the Fibrosis Index Based on Four Factors (FIB-4) and Nonalcoholic Fatty Liver Disease Fibrosis Score (NFS). Changes in parameters were analyzed using the Wilcoxon signed-rank test, whereas correlations were assessed with Spearman rank analysis.

RESULTS: A 32% decrease in mean body weight was observed 1 year after surgery (p = 2.4 × 10⁻¹¹), and 62 patients (72.9%) achieved clinical remission of diabetes. Significant decreases were observed in HbA1c (p = 1.4 × 10⁻¹¹), triglycerides (p = 3.3 × 10⁻⁸), low-density lipoprotein cholesterol (p = 2.6 × 10⁻⁴), C-reactive protein (p = 2.1 × 10⁻⁸), alanine aminotransferase (p = 3.7 × 10⁻⁹), aspartate aminotransferase (p = 1.3 × 10⁻⁵), γ-glutamyltransferase (p = 9.0 × 10⁻⁶), and alkaline phosphatase (p = 7.6 × 10⁻⁵) and in all hepatic steatosis indices (FLI: p = 7.8 × 10⁻¹⁰; St-index: p = 5.3 × 10⁻¹¹; HSI: p = 2.5 × 10⁻¹⁰; and LAP: p = 2.5 × 10⁻¹³). No significant changes were found in fibrosis indices (FIB-4: p = 0.208; NFS: p = 0.112). Decreases in steatosis indices were associated with weight loss (FLI: r = 0.503, p = 0.001; St-index: r = 0.425, p = 3.1 × 10⁻⁴; HSI: r = 0.853, p = 2.6 × 10⁻⁴; and LAP: r = 0.252, p = 0.008). Changes in LAP correlated with a decrease in HbA₁c (r = 0.355, p = 4.3 × 10⁻⁴), and changes in St-index and HSI were linked to changes in estimated glucose utilization rate (r = −0.502, p = 1.7 × 10⁻⁴ and r = −0.269, p = 0.001, respectively).

CONCLUSION: In patients with morbid obesity and type 2 diabetes mellitus, noninvasive hepatic steatosis indices decreased and fibrosis indices remained unchanged 1 year after bariatric surgery (mini-gastric bypass or sleeve gastrectomy with single-anastomosis ileal bypass).