Impact of gastric bypass surgery on the liver fibrosis of patients with extreme obesity and nonalcoholic fatty liver disease in 30-month follow-up

Impact of bariatric surgery on circulating irisin levels: a systematic review and meta‑analysis

This systematic review and meta-analysis evaluated changes in circulating irisin levels after bariatric surgery. A systematic search was performed across Embase, Scopus, PubMed, and Web of Science for this study. The meta-analysis was conducted using Comprehensive Meta-Analysis (CMA) V4 software. The overall effect size was depicted through a random-effects meta-analysis and the leave-one-out method. The meta-analysis, which included 13 studies with a total of 407 participants, showed a statistically non-significant reduction in circulating irisin levels following bariatric surgery (SMD:  - 0.089, 95% CI  - 0.281, 0.102, 95% PI:  - 0.790, 0.611, p = 0.360; I2:70.56). Our research found no significant change in irisin levels after bariatric surgery. Moreover, these findings were not associated with the type of surgery or the duration of follow-up.

Association between the cardiometabolic index and NAFLD and fibrosis

Composed of obesity and lipid parameters, the cardiometabolic index (CMI) has emerged as a novel diagnostic tool. Originally developed for diabetes diagnosis, its application has expanded to identifying patients with cardiovascular diseases, such as atherosclerosis and hypertension. However, the relationship between CMI and non-alcoholic fatty liver disease (NAFLD) and liver fibrosis in the US population remains unclear. This cross-sectional study analyzed data from the National Health and Nutrition Examination Survey (NHANES) spanning 2017-2020, involving 2996 participants aged 20 years or older. Vibration controlled transient elastography using a FibroScan® system (model 502, V2 Touch) with controlled attenuation parameter measurements identified NAFLD at a threshold of ≥ 274 dB/m, while liver stiffness measurement (LSM) results (median, ≥ 8.2 kPa) indicated fibrosis. A multifactorial logistic regression model explored the relationship between CMI and NAFLD and fibrosis. The effectiveness of CMI in detecting NAFLD and liver fibrosis was assessed through receiver operating characteristic curve analysis. Controlling for potential confounders, CMI showed a significant positive association with NAFLD (adjusted OR = 1.44, 95% CI 1.44-1.45) and liver fibrosis (adjusted OR = 1.84, 95% CI 1.84-1.85). The Areas Under the Curve for predicting NAFLD and fibrosis were 0.762 (95% CI 0.745 ~ 0.779) and 0.664(95% CI 0.633 ~ 0.696), respectively, with optimal cut-off values of 0.462 and 0.527. There is a positive correlation between CMI and NAFLD and fibrosis, which is a suitable and simple predictor of NAFLD and fibrosis.

Improvement of Triglyceride-Glucose Index Following Bariatric Surgery: a Systematic Review and Meta-analysis

BACKGROUND

Bariatric surgery is an effective intervention for the management of severe obesity and its associated comorbidities, including metabolic abnormalities. This meta-analysis aimed to evaluate the impact of bariatric surgery on the triglyceride-glucose (TyG) index, a novel marker of insulin resistance and metabolic syndrome.

METHODS

A systematic search was conducted in Embase, PubMed, Web of Science, and Scopus. The meta-analysis was performed using Comprehensive Meta-Analysis (CMA) V4 software. The overall effect size was determined by a random-effects meta-analysis and the leave-one-out approach.

RESULTS

A total of 9 trials including 1620 individuals confirmed a significant reduction in TyG following bariatric surgery (weighted mean difference (WMD) - 0.770, 95% CI - 1.006, - 0.534, p < 0.001). In a sub-analysis according to the type of bariatric surgery there was a significant reduction in TyG index for Roux-en-Y gastric bypass (WMD - 0.775, 95% CI - 1.000, - 0.550, p < 0.001), and sleeve gastrectomy (WMD - 0.920, 95% CI - 1.368, - 0.473, p < 0.001). In a sub-analysis according to the follow-up duration there was similarly a significant reduction in TyG index for both < 12 months (WMD - 1.645, 95% CI - 2.123, - 1.167, p < 0.001), and ≥ 12 months follow-up (WMD - 0.954, 95% CI - 1.606, - 0.303, p < 0.001).

CONCLUSION

The results of this meta-analysis demonstrated a significant reduction in the TyG index following bariatric surgery, indicating improved insulin sensitivity and metabolic health. These findings highlight the potential of bariatric surgery as a valuable therapeutic option for individuals with obesity and its metabolic consequences.