Effects and resource implications of one anastomosis gastric bypass procedure in comparison to sleeve gastrectomy and roux n y gastric bypass in obese patients: A systematic review and meta-analysis

Kashangura, Majirija Rufaro

Effects and resource implications of one anastomosis gastric bypass procedure in comparison to sleeve gastrectomy and roux n y gastric bypass in obese patients: A systematic review and meta-analysis

Thesis / Dissertation

2024

Publisher

University of Cape Town

Department

Division of General Surgery

Faculty

Faculty of Health Sciences

Abstract

Background One anastomosis gastric bypass (OAGB) is a proposed alternative to Roux n Y gastric bypass (RYGB) and sleeve gastrectomy (LSG) which are the main bariatric operations in many centres. It is a restrictive and malabsorptive weight loss surgery thought to be simpler, having a small learning curve and shorter intraoperative time. However, its effects and safety compared to other methods remains uncertain. Objectives We aim to evaluate the available evidence from randomised controlled trials (RCTs) on effects, resource input and safety of OAGB in comparison to LSG and RYGB in obese adults and children, with a view of ascertaining the optimal technique especially in resource constrained environments. Methods We searched MEDLINE (PubMed); Embase (Ovid); Central Register of Controlled Trials (CENTRAL, Cochrane Library); Web of Science Core Collection, specifically Science Citation Index Expanded, Social Sciences Citation Index, Conference Proceedings Citation Index (Clarivate); CINAHL (EBSCOHost); Scopus; LILACS (Virtual Health Library) from Jan 2001 when OAGB was first described to August 2021. We identified all RCTs regardless of language or publication status using two search strategies, the primary strategy relating to effects and safety and the complementary strategy for health economic evaluations. We included all RCTs with adults or children with body mass index (BMI) greater than 40 or greater than 35 with comorbidities comparing OAGB to either LSG or RYGB with effects, safety, or resource implication data. Two authors independently identified the studies for inclusion, collected the data and assessed the risk of bias (ROB). We performed the meta-analyses using the Review Manager 5.4. We calculated the risk ratio (RR) for dichotomous outcomes and mean difference (MD) for continuous outcomes with 95% confidence intervals and used the random - effects model. Where meta-analysis was inappropriate or not possible a narrative synthesis was given. We used the Cochrane ROB-2 tool to assess for ROB. We used GRADE to assess the certainty of evidence for the outcomes in the summary of findings. Results From 7 271 studies we included 34 studies; 10 being published data,12 conference abstracts and 13 ongoing trials one of them with preliminary results. All participants were adults. None of the studies in the review reported on cost of the procedure or any surgery related mortality. OAGB vs LSG Total of 147 patients in the OAGB arm were compared to 146 in the LSG arm in 5 included studies (1 study had 3 publications at 1, 3 and 5 years). OAGB results in little or no difference in comorbid resolution compared to LSG for all outcomes except hypertension and diabetes at 5 years where OAGB likely results in large increase in complete diabetes resolution; RR 1.5 (1.10, 2.04). and hypertension RR 1.51 (1.03, 2.19), low evidence from one trial. OAGB likely results in large increase in estimated weight loss percentage (EWL%) consistently up to five years where EWL% is -9.34 (- 16.39, -2.29), 5 RCTs, 635 participants. Operation time is likely longer compared with LSG MD 19.04 minutes (6.49%, 31.6%), 3 RCTs, 304 participants, moderate certainty evidence. OAGB may result in an increase in bile reflux RR 1.5 (0.58, 3.88) though the evidence remains uncertain. OAGB may result in more malnutrition compared to LSG RR 2.09 (0.94, 4.63), 3 RCTs, 234 participants, low certainty evidence. Recidivism was only in 3 patients in 2 RCTS after LSG compared to OAGB, moderate certainty evidence of little or no difference. OAGB likely results in slightly better quality of life scores (QOL) including comorbidities compared to LSG up to 5 years. At 5 years, QOL is likely better after OAGB with or without comorbidities. OAGB vs RYGB Two hundred and forty-four participants had OAGB vs 254 in RYGB in 5 included studies. OAGB may result in little to no difference in comorbid resolution at 1 year: complete diabetic remission RR 0.86 (0.67, 1.10), 2 RCTs moderate certainty evidence. OAGB may result in increased EWL% compared to RYGB MD -4.93% (- 7.88%, -1.99%), 5 RCTs, 575 participants. Operation time is likely shorter with OAGB compared to RYGB MD -34.3 (-45.76, - 22.84) minutes with little or no difference in length of stay. OAGB likely results in large increase in bile reflux compared to RYGB RR 17.25 (3.13, 94.97), 3 RCTs, 322 participants with 1 report of intestinal metaplasia in the OAGB arm. The evidence is very uncertain from 2 RCTs, 128 participants about the effect of OAGB on malnutrition rates compared to RYGB: RR 2.28 (0.13, 40.45). There is little or no difference in QOL and reoperation rates compared to RYGB. Conclusion Except for weight loss and operative times, the evidence remains uncertain comparing the effects and safety of these 3 methods. From the limited data we have, OAGB attains as good outcomes as RYGB which is the preferred option in most setting, with additional significantly better weight loss. Using surrogates of theatre time and number of staples used OAGB appears to save time and to be a cheaper option than RYGB. However, there are still concerns of likely increase in bile reflux and no evidence of effect on malnutrition after surgery. More RCTs with larger sample sizes in low-income areas are needed to explore these outcomes further. More long-term studies will explore the possibility of development of gastric cancer. None of the studies reported on cost of the procedures to inform decision making in low-income area.

Keywords

General Surgery

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