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ASGARD Trial: BPD-DS may not be a better surgical strategy than RYGB for patients with a BMI 50-60

The ten-year outcomes from the ’Laparoscopic Roux-en-Y Gastric Bypass Versus Laparoscopic Biliopancreatic Diversion (BPD)- Duodenal Switch for Superobesity (ASGARD)’ trial by researchers from Norway and Sweden, has revealed that BMI reduction was greater after Duodenal Switch (DS), but Roux-en-Y-gastric bypass (RYGB) had a better risk profile over ten years. They concluded that biliopancreatic diversion with DS may not be a better surgical strategy than RYGB for patients with a BMI of 50-60.

The ASGARD study is a randomised clinical trial performed at Oslo University Hospital, Oslo, Norway, and Sahlgrenska University Hospital, Gothenburg, Sweden. Patients with a BMI 50-60 and aged 20 to 50 years were included between March  2006 and August 2007.


Roux-en-Y gastric bypass and DS were performed laparoscopically. In RYGB, a gastric pouch of less than 25 mL was anastomosed to an antecolic-antegastric alimentary limb of 150 cm with a linear stapler and complementary suturing. The biliopancreatic limb was 50 cm. The 1-stage DS procedure included a sleeve gastrectomy stapled loosely along a 30F to 32F bougie. The duodenum was divided 2 to 3 cm distal to the pylorus. The alimentary limb was 200 cm, the common channel was 100 cm, and the length of the biliopancreatic limb was not measured. Cholecystectomy was not performed during either procedure. The primary outcome was change in BMI after ten or more years.


In total, 48 of 60 patients (80%) attended consultations ten years or more after surgery (23 in the RYGB group and 25 in the DS group). The mean (SD) age was 48.0 (6.0) years overall, 47.8 (6.9) years for RYGB, and 48.5 (5.3) for DS. A total of 35 patients (73%) were women and 13 (27%) were men, with 18 women (78%) and five men (22%) in the RYGB group and 17 women (68%) and eight men (32%) in the DS group. Median follow-up was 12 (range, 9-13) years.


Outcomes

At follow-up, the mean BMI reductions were 11.0 (95% CI, 8.3-13.7) for the RYGB group and 20.3 (95% CI, 17.6-23.0) for the DS group, with a mean between-group difference of 9.3 (95% CI, 5.4-13.1; p<0.001). Total weight loss was 20.0% (95% CI, 15.3%-24.7%) for the RYGB group and 33.9% (95% CI, 27.8%-40.0%) for the DS group (p=0.001).


The investigators reported that both procedures induced maximal weight loss at approximately two years with subsequent weight regain. Mean weight regain from the nadir was 19.8 (95% CI, 12.0-27.6) kg for the RYGB group and 15.9 (95% CI, 8.6-23.2) kg for the DS group, with a mean between-group difference of 3.9 (95% CI, 6.5-14.3) kg (p=0.45). Mean BMI at follow-up was 44.5 (95% CI, 41.6-47.4) for the RYGB group and 35.9 (95% CI, 32.8-39.1) for the DS group, with a mean between-group difference of 8.6 (95% CI, 4.4-12.8) (p<0.001). The proportions of patients with BMI of 40 or greater were 16 of 23 (70%) after RYGB and 8 of 25 (32%) after DS (p=0.009).


There were no significant differences in the prevalence of type 2 diabetes, dyslipidaemia or metabolic syndrome between the groups at follow-up. Mean serum lipid levels improved more in the DS group except for high-density lipoprotein cholesterol levels, which increased more after RYGB. Mean HbA1c level was 5.7% (95% CI, 5.4%-6.0%) for the RYGB group and 5.0% (95% CI, 4.7%-5.3%) for the DS group (p=0.005) ten years after surgery, corresponding to 39 (95% CI, 35-42) mmol/mol for RYGB and 31 (95% CI, 28-34) mmol/mol for DS (p=0.006).


The total number of adverse events was 97 after RYGB and 135 after DS (p=0.02), with a mean (SD) number of adverse events per patient of 3.1 (2.5) and 4.6 (2.6), respectively (p=0.01). After RYGB, 21 of 31 patients (68%) were admitted to the hospital for any reason, and 18 of 29 (62%) after DS (p=0.65). The number of hospital admissions and abdominal surgical procedures were similar. Seven of 31 patients (23%) in the RYGB group and 11 of 29 (38%) in the DS group underwent body reconstructive surgery (p=0.29).


Additional outcomes included:

  • More patients underwent cholecystectomies after DS (11 in the DS group vs 4 in the RYGB group; p=0.03).

  • Four of 29 patients (14%) developed protein-caloric malnutrition after DS compared with none after RYGB (p=0.02).

  • Symptoms of gastroesophageal reflux were more prevalent after DS (10 vs 4 patients; p=0.05).

  • One patient died 13 years after DS and two patients died four and five years after RYGB.

  • Among patients in the DS group, 21 of 25 (84%) had one or more vitamin deficiency compared with 11 of 23 (48%) after RYGB (p=0.005).

  • Osteoporosis and osteopenia combined, there was a higher incidence of reduced bone mass in the DS group (11 in the RYGB group vs 21 in the DS group p=0.004).

  • Scores on the SF-36 were similar across groups at ten years.


“Despite the initial hypothesis in this randomised clinical trial that DS was a superior option to RYGB in patients with a BMI of greater than 50, we have ultimately concluded with the opposite, and DS with a short common channel (<200 cm) is currently no longer used in our institutions,” they concluded. “For strictly selected patients with particularly high BMI and related comorbidity, the risk and benefit balance may justify the use of DS in experienced centres. The developing landscape of obesity treatment may suggest prioritising bariatric techniques with the most optimal risk-benefit profile and adding modern weight loss medications when needed.”


The findings were reported in the paper, ‘Ten-Year Outcomes Following Roux-en-Y Gastric Bypass vs Duodenal Switch for High Body Mass Index - A Randomized Clinical Trial’, published in JAMA Network Open. To access this paper, please click here

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