Effects of bariatric surgery and dietary intervention on insulin resistance and appetite hormones over a 3 year period

Sex-differential testosterone response to long-term weight loss

OBJECTIVES

Obesity-associated gonadal dysfunction is a common comorbidity in patients seeking weight loss interventions. We examined the incremental effect of weight loss on gonadal axes in men and women over 3 years. Changes in sex hormones were compared between dietary intervention (Diet) and bariatric procedures: Roux-en-Y gastric bypass (RYGB), sleeve gastrectomy (SG) and laparoscopic adjustable gastric banding (LAGB). Additional analysis assessed changes in corticotropic, somatotropic and thyroid axes after weight loss interventions.

METHODS

This prospective, observational study included 61 adults with Body Mass Index >30 kg/m2, mean age 51 (SD = 11) years. Endocrine parameters were measured at baseline and at 6 timepoints over 36-months.

RESULTS

For each 1 kg of weight lost, between baseline and 36 months, total testosterone increased by 0.6% (95% CI: 0.2%, 1.0%, p = 0.002) in males and decreased by 0.8% (95% CI: -1.4%, -0.3%, p = 0.003) in females. These changes remained statistically significant when controlled for age and for menopausal status in females. At 36 months, in comparison with Diet, RYGB women had lower total testosterone by 54% (95% CI: -90%, -17%, p = 0.004), reduced free androgen index (FAI) by 65% (95% CI; -114%, -17%, p = 0.009) while SG had reduced FAI by 39% (95% CI; -77%, 0%, p = 0.05). No such differences between groups were noted for male subjects. Adrenocorticotropic hormone declined by 0.3% (95% CI: 0.0, -0.5%, p = 0.05), insulin-like growth factor-1 increased by 0.4% (95% CI; 0.2%, 0.7%, p = 0.005), without such thyrotrophin change for each 1 kg of weight loss, for entire cohort, over 36 months.

CONCLUSIONS

The testosterone changes observed in this study were proportional to the amount of weight loss. In females, reduction in androgens was independent of age and menopausal status and more pronounced after bariatric procedures. This study finding warrants further clinical research to explore an impact of androgen reduction on functional and cognitive status in postmenopausal women. The observed changes in pituitary hormones may contribute to the metabolic benefits of bariatric surgery.

Evaluating Laparoscopic Sleeve Gastrectomy for Morbid Obesity: A Prospective Follow-Up Study

Background Laparoscopic sleeve gastrectomy (LSG) has become a primary option within bariatric surgery (BS), exhibiting favorable outcomes in terms of weight reduction and improvement of associated health conditions. This study was conducted to assess the outcomes of LSG in morbid obesity (MO) in terms of weight reduction and improvement of comorbidities. Materials and methods A prospective follow-up study was conducted from January 2021 to January 2023 at the Department of Surgery, 7 Air Force Hospital, Kanpur. The study was approved by the institutional ethical committee with protocol no. IEC/612/2020, including 25 patients diagnosed with MO (BMI >40kg/m2) who underwent LSG. Patients were followed up at 1, 3, 6, and 12 months after surgery to track improvements in comorbidities and weight loss. Pre- and post-operative photos were taken, and any complications during the follow-up period were noted. Results Most participants in the study were middle-aged individuals, and 84% of the cohort had common comorbidities such as hypertension (HTN) and diabetes mellitus (DM). LSG led to significant and sustained weight loss, with patients achieving an average reduction of 31.56 kg by the 12th month following the surgery. Moreover, substantial improvements in comorbidities, particularly HTN (76.9%) and DM (80%), were observed. However, not all comorbidities exhibited similar rates of recovery, highlighting the need for tailored management strategies. Using a correlation test, no significant correlation was found between the percentage over ideal body weight (IBW) and the reduction in excess weight, as indicated by a p-value exceeding 0.05. Conclusion LSG is an effective treatment for severe obesity, delivering significant weight loss and notable improvements in metabolic health and overall quality of life.

Assessing the Impact of Bariatric Surgery on Retinol-Binding Protein 4 (RBP4): A Systematic Review and Meta-Analysis

This study aimed to analyze changes in retinol-binding protein 4 (RBP4) levels before and after bariatric surgery in obese individuals. Bariatric surgery is a safe and effective treatment for morbid obesity, impacting molecules like RBP4. A systematic review and meta-analysis of 12 relevant studies were conducted, utilizing databases such as PubMed, Cochrane Central, Web of Science, and Scopus. Significant differences in RBP4, glucose, and BMI levels pre- and post-surgery were observed. Meta-regression analysis explored associations with age, pre-BMI, triglycerides, glucose, and post-insulin levels. Findings suggest RBP4 may improve insulin sensitivity after bariatric surgery, warranting further investigation as a potential pharmacotherapeutic target. These results highlight the importance of understanding RBP4's role in the context of bariatric surgery and its implications for improving metabolic health in obese individuals.

Beyond Weight Loss: A Comprehensive Review of Pregnancy Management following Bariatric Procedures

The increasing prevalence of bariatric surgery among women of childbearing age raises critical questions about the correct management of pregnancy following these procedures. This literature review delves into the multifaceted considerations surrounding pregnancy after bariatric surgery, with a particular focus on the importance of preconception counselling, appropriate nutrition assessment, and the necessity of correct folic acid supplementation. Key areas of investigation include nutrient absorption challenges, weight gain during pregnancy, and potential micronutrient deficiencies. Examining the relationship between bariatric surgery and birth defects, particularly heart and musculoskeletal issues, uncovers a twofold increase in risk for women who underwent surgery before pregnancy, with the risk emphasized before folic acid fortification. In contrast, a nationwide study suggests that infants born to mothers with bariatric surgery exhibit a reduced risk of major birth defects, potentially associated with improved glucose metabolism. In addition, this review outlines strategies for managing gestational diabetes and other pregnancy-related complications in individuals with a history of bariatric surgery. By synthesizing existing literature, this paper aims to provide healthcare providers with a comprehensive framework for the correct management of pregnancy in this unique patient population, promoting the health and well-being of both mother and child.

Retinol binding protein 4 and type 2 diabetes: from insulin resistance to pancreatic β-cell function

BACKGROUND AND AIM

Retinol binding protein 4 (RBP4) is an adipokine that has been explored as a key biomarker of type 2 diabetes mellitus (T2DM) in recent years. Researchers have conducted a series of experiments to understand the interplay between RBP4 and T2DM, including its role in insulin resistance and pancreatic β-cell function. The results of these studies indicate that RBP4 has a significant influence on T2DM and is considered a potential biomarker of T2DM. However, there have also been some controversies about the relationship between RBP4 levels and T2DM. In this review, we update and summarize recent studies focused on the relationship between RBP4 and T2DM and its role in insulin resistance and pancreatic β-cell function to clarify the existing controversy and provide evidence for future studies. We also assessed the potential therapeutic applications of RBP4 in treating T2DM.

METHODS

A narrative review.

RESULTS

Overall, there were significant associations between RBP4 levels, insulin resistance, pancreatic β-cell function, and T2DM.

CONCLUSIONS

More mechanistic studies are needed to determine the role of RBP4 in the onset of T2DM, especially in terms of pancreatic β-cell function. In addition, further studies are required to evaluate the effects of drug intervention, lifestyle intervention, and bariatric surgery on RBP4 levels to control T2DM and the role of reducing RBP4 levels in improving insulin sensitivity and pancreatic β-cell function.

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.

Prior bariatric surgery is associated with lower mortality and resource utilization following small bowel obstruction

Background

Small bowel obstruction (SBO) is a complication of bariatric surgery. However, outcomes of surgical intervention for SBO among patients with prior bariatric surgery remain ill-defined. We used a nationally representative cohort to characterize the outcomes of the SBO management approach in patients with a prior bariatric operation.

Methods

All adult hospitalizations for SBO were tabulated from the 2018-2020 National Readmissions Database. Patients with a prior history of bariatric surgery comprised the Bariatric cohort (others: Non-Bariatric). Multivariable models were subsequently developed to evaluate the association of prior bariatric surgery with outcomes of interest.

Results

Of an estimated 299,983 hospitalizations for SBO, 15,788 (5.3 %) had a history of prior bariatric surgery. Compared to Non-Bariatric, Bariatric patients were younger (54 [46-62] vs 57 [47-64] years, P < 0.001) and were more frequently privately insured (45.1 vs 39.4 %, P < 0.001). On average, the Bariatric more frequently underwent operative management, relative to Non-Bariatric (44.8 vs 29.7 %, P < 0.001). Following risk adjustment, among those surgically managed, Bariatric demonstrated lower odds of mortality (Adjusted Odds Ratio [AOR] 0.69, 95 % Confidence Interval [CI] 0.55-0.87) compared to Non-Bariatric. Bariatric also demonstrated lower odds of infectious and renal complications. Furthermore, the Bariatric cohort had lower costs, length of stay, and non-home discharge.

Conclusions

Patients with prior bariatric surgery demonstrated a lower likelihood of mortality, decreased complications, and reduced resource utilization, relative to others. As the incidence of bariatric surgery continues to rise, future work is needed to minimize the incidence of SBO among these patients, especially in the current era of value-based healthcare.

Diabetic Markers, Five Years after Bariatric Surgery

Background: Bariatric surgery delivers substantial weight loss for obese patients with comorbidities like diabetes mellitus. We aimed to investigate the impacts of bariatric surgery on diabetic markers after 5 years of follow-up. Methods: This is a retrospective study on patients with diabetes and a history of bariatric surgery between 2016-2017. The diabetic markers before and 5 years following surgery, including a lipid profile, glucose level, and the required antidiabetic medications, were evaluated. Results: 34 consecutive patients were included, 30 (88.2%) women, with a mean age of 52.71±8.53 years. The majority (65%) of surgeries were Roux-en-Y gastric bypass (RYGB), and the remaining were one anastomosis gastric bypass (OAGB) and sleeve gastrectomy (SG). The serum levels of diabetic markers reduced during follow-up (P=0.001), except for high-density lipoprotein levels and serum total cholesterol, which increased (P=0.011, P=0.838). Low-density lipoprotein levels reduced, but it was insignificant (P=0.194). Surgery types had affected the changes of diabetic markers (P>0.05). Demand for oral medication was reduced significantly, but insulin injection reduction was not significant (P=0.006 and P=0.099, respectively). Conclusion: Our study showed favorable bariatric surgery results on patients with diabetes in long-term follow-up. However, dyslipidemia is still a concern.