Published on: 21 July 2025

Introduction

Obesity is a chronic, pandemic disease affecting millions globally, with nearly 2.5 billion adults overweight and 890 million living with obesity as of 2022, according to the World Health Organization. Metabolic and bariatric surgery (MBS) has proven effective in reducing weight and treating obesity-related comorbidities. Sleeve gastrectomy (SG) is currently the most frequently performed bariatric procedure worldwide due to its short-term efficacy and relatively low mortality.

Despite its popularity, SG has a significant rate of insufficient clinical response, reported to be as high as 50% at 6 to 8 years post-operation. This insufficiency is characterized by weight regain and the development of postoperative complications such as gastroesophageal reflux disease (GERD), with incidence rates between 7% and 20%. The International Federation for the Surgery of Obesity and Metabolic Disorders (IFSO) defines insufficient clinical response as total weight loss (TWL%) less than 20% at 12 months.

Several factors contribute to this insufficient response, including body mass index (BMI), inadequate gastric restriction, progressive dilation of the gastric sleeve, and technical variations during the initial surgery. When SG fails to achieve the desired outcomes, revisional surgery becomes necessary to address weight recurrence, GERD, and other obesity-related comorbidities such as type 2 diabetes mellitus (T2DM), hypertension, and obstructive sleep apnea (OSA.

Revisional Procedures

Common revisional procedures include:

• Roux-en-Y Gastric Bypass (RYGB): Considered the gold standard for revisional surgery, RYGB involves creating a small gastric pouch and bypassing a portion of the small intestine, which provides restriction and malabsorption. It is particularly effective in resolving GERD symptoms and offers sustained weight loss with lower risks of severe nutritional deficiencies compared to other techniques.
• One-Anastomosis Gastric Bypass (OAGB): A simplified procedure involving a single gastrojejunal anastomosis, combining restriction and malabsorption. It has gained popularity for its technical simplicity, shorter operative time, and promising metabolic benefits, including remission of T2DM and hypertension. However, it may carry risks such as postoperative GERD and malabsorption of essential nutrients (iron, vitamin B12).

Other revisional options like single-anastomosis duodeno-ileal bypass with sleeve gastrectomy (SADI-S) exist but are less frequently compared in this context.

Objective

This systematic review and meta-analysis aimed to compare the effectiveness and safety of RYGB versus OAGB as revisional procedures after insufficient clinical response following SG. The evaluated outcomes included:

• Weight loss (TWL% and BMI changes)
• Remission of obesity-related comorbidities (T2DM, hypertension, GERD)
• Postoperative complications
• Operative time

Methods

Following PRISMA 2020 guidelines, a comprehensive literature search was conducted across six databases (PubMed, Scopus, Web of Science, Cochrane, Ovid/Medline, and Embase) up to November 30, 2024. The search strategy used the PICO framework:

• Population: Adults with insufficient clinical response or complications after SG
• Intervention: Revisional RYGB
• Comparator: Revisional OAGB
• Outcomes: Weight loss, comorbidity remission, complications, operative time

Inclusion criteria encompassed randomized controlled trials (RCTs) and observational studies directly comparing RYGB and OAGB. Excluded were case reports, series, prior reviews, pediatric studies, and incomplete data reports.

Data extraction was performed independently by two reviewers, focusing on study characteristics, patient demographics, and clinical outcomes. Risk of bias was assessed using RoB 2.0 for RCTs and ROBINS-I for observational studies. Statistical analyses employed risk ratios (RR) and mean differences (MD) with 95% confidence intervals (CI), using random-effects models when heterogeneity was significant.

Results

Study Selection and Characteristics

From 236 initial articles, 5 studies met the inclusion criteria, comprising one RCT, two cohorts, one case-control, and one cross-sectional study, with a combined sample size involving over 300 patients undergoing revisional surgery. The included studies spanned multiple countries, predominantly Germany, Poland, Egypt, and Austria.

Risk of bias was low for the RCT and moderate for the observational studies, emphasizing the need for cautious interpretation.

Weight Loss Outcomes

• Total Weight Loss Percentage (TWL%): Data from four studies (316 patients) showed that OAGB resulted in significantly greater TWL% at 1 year post-surgery compared to RYGB (MD = −1.24%; 95% CI: −1.94 to −0.53; p = 0.0006). The moderate heterogeneity (I² = 60%) reflected variations in study designs and populations but consistently favored OAGB.
• Body Mass Index (BMI) Reduction: Four studies involving 353 patients found no significant difference between RYGB and OAGB in BMI reduction at 1 year (MD = 0.00; 95% CI: −1.24 to 1.24; p = 1.00), indicating comparable effects on BMI despite the difference in TWL%.

The superior weight loss with OAGB is attributed to its stronger malabsorptive component and enhanced hormonal responses, such as increased GLP-1 and PYY secretion, which suppress appetite and improve glycemic control. However, the potential for nutritional deficiencies with OAGB necessitates vigilant long-term follow-up.

Comorbidity Remission

• Type 2 Diabetes Mellitus (T2DM): Three studies with 52 patients reported no statistically significant difference in T2DM remission between RYGB and OAGB (RR = 0.97; 95% CI: 0.79–1.21; p = 0.81). However, some individual studies suggested a trend favoring OAGB’s malabsorptive advantage.
• Arterial Hypertension: Similar remission rates were observed in three studies (75 patients), with no significant difference (RR = 0.85; 95% CI: 0.60–1.22; p = 0.38). This suggests that hypertension improvement is more related to weight loss magnitude than the surgical technique.
• Gastroesophageal Reflux Disease (GERD): Two studies (130 patients) demonstrated comparable remission rates between both procedures (RR = 1.00; 95% CI: 0.86–1.17; p = 0.97). Although some evidence suggests higher postoperative GERD incidence with OAGB, RYGB remains preferred in severe GERD cases.

Safety and Operative Time

• Postoperative Complications: Four studies (418 patients) revealed no significant difference in complication rates between RYGB and OAGB (RR = 0.89; 95% CI: 0.67–1.18; p = 0.42), indicating comparable safety profiles. This aligns with findings that surgical expertise and patient selection critically influence outcomes.
• Operative Time: Three studies (338 patients) showed OAGB had a significantly shorter operative time than RYGB by approximately 30 minutes (MD = 30.10 min; 95% CI: 27.89–32.32; p < 0.00001). This reduction reflects the technical simplicity of OAGB and may translate into faster recovery and fewer intraoperative risks.

Discussion

This systematic review highlights that OAGB offers a modest but statistically significant advantage in total weight loss compared to RYGB when performed as revisional surgery after failed SG. The enhanced weight loss with OAGB is explained by its combined restrictive and malabsorptive mechanism, leading to improved hormonal modulation which favors appetite suppression and metabolic regulation.

Despite this, BMI did not differ significantly between the two procedures, suggesting that BMI alone may not fully capture the clinical effectiveness of revisional bariatric surgery. Factors such as prior nutritional status, metabolic improvements, and patient adherence to postoperative care may influence BMI outcomes more than the surgical technique.

Both procedures showed similar effectiveness in the remission of obesity-related comorbidities, including T2DM and hypertension, with a non-significant trend favoring OAGB for diabetes remission. GERD remission rates were comparable, but RYGB may be superior for patients with severe preoperative reflux due to lower postoperative GERD risk.

Safety profiles were analogous, with no significant differences in postoperative complications, underscoring the importance of surgical expertise and individualized patient assessment. The significantly shorter operative time for OAGB may reduce overall procedural risks, costs, and enhance recovery.

Limitations

The review acknowledges several limitations:

• Heterogeneity in study designs, populations, and follow-up durations limits definitive conclusions.
• Inclusion of observational studies alongside an RCT introduces varying risk of bias.
• Short-term follow-up in most studies restricts assessment of long-term outcomes and nutritional consequences.
• Nutritional deficiencies and quality-of-life assessments were not uniformly reported.

These limitations highlight the need for larger, high-quality randomized controlled trials with standardized outcome measures and longer follow-up to better delineate the optimal revisional procedure after failed sleeve gastrectomy.

Conclusion

OAGB demonstrates superior total weight loss and shorter operative times compared to RYGB as revisional surgery after insufficient clinical response to sleeve gastrectomy. Both procedures effectively manage obesity-related comorbidities with comparable safety profiles. RYGB remains preferable in patients with severe preoperative GERD due to its better control of reflux symptoms.

Clinicians should balance the benefits of greater weight loss and shorter surgery duration with the potential for nutritional deficiencies associated with OAGB. Long-term nutritional monitoring and patient selection are essential to optimize outcomes.

Further robust, long-term studies are warranted to establish clear clinical guidelines and personalize revisional bariatric surgery strategies for patients with failed sleeve gastrectomy.

SOURCE/READ FULL ARTICLE:  https://pubmed.ncbi.nlm.nih.gov/40691334/

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