Short summary of metabolic and bariatric surgery (MBS) in 2025 Metabolic and bariatric surgery (MBS) *Have repeatedly been shown to provide significant and long lasting weight loss results with markedly enhanced quality of life, improvement and prevention of obesity related complications and increased life expectancy *Have better weight loss and diabetes resolution compared to medical management and obesity management medications (OMM)   OMM *Results for OMM remain unknown beyond 2 to 3 years *OMM are expensive, currently prescribed for a limited period of time, not on PBS (for non diabetic), may have side effects and not well tolerated by everyone

Long term results for MBS   Roux Y gastric bypass Long term studies (15-20 years after RYGBP) reported: *about 24.3 to 28% total body weight loss (TWL) up to 20 years post op *nadir is achieved 2 years after surgery then recurrent weight gain 2-10 years with weight stabilization after 10 years *however 1.3 to 3.5% patients did not achieve adequate weight loss (20% TWL) initially *re-operations may be needed for internal hernia (1.05%) +/- small bowel obstruction, marginal ulcers and candy cane syndrome *re-operations to elongate the BP limb may provide a further 24% weight loss after 3 years *RYGBP conversion to BPD-DS or SADI-S can be considered in selected patients but these are associated with high peri-operative morbidity and long term nutritional complications (however nowadays OMM may be a easier alternative)   Weight regain/recidivism after RYGBP has been reported, patients may regain up to 17% of their maximal weight loss after 4 years   The RYGBP is the best primary or salvage surgical procedure for obesity and refractory reflux but up to 22% of patients may still report reflux symptoms post operatively, partly from recurrent or de novo hiatus hernia *Hiatus hernia repair after RYGBP has been described to have over 70% symptoms resolution and 23% symptom improvement but there may be recurrence of symptoms in 11% Sleeve gastrectomy Recent review of sleeve gastrectomy results >10 years reported: *24.4% TWL *but 32.3% have persisting or recurrent de novo reflux symptoms and 19.2% re-operation rate   Sleeve gastrectomy is still the most common MBS performed worldwide. *However in Taiwan the sleeve plus (SASJ) has become the number primary bariatric procedure partly driven by social media promotions. RYGBP vs LSG One recent systematic review and meta-analysis of 9 randomized trial comparing RYGBP and sleeve for their long term (> 5 years) outcomes reported: *RYGBP have greater excess weight loss (EWL), total body weight loss (TBW), excess BMI loss (EBL), diabetes remission and GOR improvement *Sleeve is associated with lower late major complications *No significant differences in the two groups with regards to HbA1C, dyslipidaemia, hypertension, OSA, joint improvement, early minor/major complications or late minor complications ***Note there is greater reduction in HbA1C and higher remission rate for T2DM in the RYGBP group in the short and medium term but no demonstrable statistical significance This is different to previous meta-analyses which reported no significant differences in excess weight loss between the two groups *No doubt with longer follow up these differences became more evident *Also the rate of post op vitamin deficiencies and risk of malnutrition is higher in the RYGBP group Some studies also indicated that the bypass group have lower risk for major adverse cardiovascular event (MACE) due to reduced myocardial infarction rates in the long term     OAGB vs RYGBP Recent meta-analysis of 12 randomized control trials (992 patients) reported: *non inferiority of the OAGB compared to RYGBP in the remission of obesity related co-morbidities (remission of T2DM) and post operative complications (bile reflux and de novo GOR) *RYGBP is superior for reduction in bile and de novo acid reflux *The YOMEGA trial also reported comparable results for T2DM remission rates for both types of procedure     Others Recent reports for primary BPD and BPD-DS resulted in 10% better TWL and more durable weight loss than the RYGBP but there are serious risk for frequent and long term nutritional complications Conversion sleeve gastrectomy to OAGB or RYGBP One systematic review and meta-analysis found: Greater weight loss (1.24% advantage) in the OAGB group compared to RYGBP potentially due to the longer BP limb, stronger hypo absorption component and its ability to stimulate greater hormonal response (GLP-1 and PYY) which contribute to appetite suppression and improved glycaemic outcomes *But OAGB has more reports of iron, calcium, fat soluble vitamins, B12 deficiencies There were no overall statistically significant in remission outcome for T2DM or HPT remission between the OAGB vs RYGBP *However there is a slight advantage in glycaemic control with OAGB There were no statistically significant outcome in reflux between the two groups *However OAGB may increase post op reflux in severe cases and most surgeons still prefer the RYGBP for post sleeve patients with severe acid/bile reflux   Both procedures have a similar safety profile, no significant differences in post op complications *The OAGB has a shorter operative time and avoids the potential complication with the second anastomosis

Brief summary of the history of metabolic bariatric surgery (MBS) in the last 30-50 years   Surgeries that had been popular in the past but now there are: *Abandonment of jejuno-ileal bypass (JIB) and vertical banded gastroplasty (VGB) *Decline of laparoscopic gastric band (LAGB) *Decline of the classical bilio-pancreatic diversion (BPD) due to severe GIT side effects and malnutrition  (complication rates up to 13%)   Historically and from vigorous scientific studies these procedures have proven safety and efficacy: *Laparoscopic sleeve gastrectomy (LSV), initially performed in 1988 (open) and in 1999 (laparoscopic) *Laparoscopic Roux Y gastric bypass (RYGBP), first described in 1967   The procedures that have now been endorsed by IFSO and ASMBS include: *Laparoscopic one anastomosis gastric bypass (OAGB), first introduced in 2001 *Single anastomosis duodeno-ileal bypass with sleeve (SADI-S), first introduced around 2007 but studies on long term safety and nutritional deficiencies are needed   In the foreseeable future *The sleeve gastrectomy will still remain as the most popular primary bariatric metabolic surgery across the whole world *The gastric bypass (RYGBP and OAGB) will remain as the next most popular primary and the most popular revision/conversion bariatric metabolic surgery *The RYGBP may be the preferred option as the primary procedure for obese patients with severe reflux (Grade C or D oesophagitis) , peptic stricture +/- non dysplastic Barrett’s oesophagus ***study found that 47% improvement rate in GOR symptoms and 79.4% discontinuation rate for PPI medications     Newer procedures introduced in the last few years include: *Single anastomosis sleeve ileal (SASI) bypass *Sleeve gastrectomy with transit bipartition *Ileal interposition Time will tell if these  procedures will prove to be more beneficial than the primary sleeve alone or if these procedures will decline as well due to the unwanted complications

MBS and OMM   Metabolic and bariatric surgery have significant impact on sustained long term weight loss, resolution/control of medical co-morbidities, reduce complications of obesity, improve long survival/longevity and beneficial to the health care budget *But the types of surgeries have evolved a lot and become more refined over the years (see table below)   In the last few years the introduction of obesity medical management (OMM) as an alternative and/or adjunct medication before or after MBS have also changed the algorithm for the management of obesity and metabolic disorders

Final note and key point   The long term success is dependent on both the surgery and patient adherence to lifestyle modification   The joint care model involving multidisciplinary approach are needed with the primary GP, physician, surgeon, dietitian, psychologist, exercise physiotherapist and good family support   MBS with OMM may offer the best long term result in weight loss maintenance and treatment of weight regain   Revision MBS will become more common in the future as well for treating complications of primary procedure and weight regain   In the future the introduction of artificial intelligence (AI) may offer an additional tool that personalize patient care, facilitate real time monitoring and help to predict surgical outcome with better accuracy and better safety profile Nutrigenomics and nutrigenetics may also increase our knowledge of obesity, its related diseases and management

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