top of page

MBS provides safe and rapid weight loss for patients with Prader-Willi Syndrome

Updated: Feb 2, 2023

The current data on metabolic and bariatric surgery (MBS) in patients with Prader-Willi Syndrome (PWS) reveal that laparoscopic sleeve gastrectomy (LSG), gastric bypass (GB) and biliopancreatic diversion (BPD, with or without with duodenal switch (DS)) provide rapid weight loss safely and alter the natural progression of weight gain seen in patients with PWS. The findings were reported in the paper, ‘Metabolic and Bariatric Surgery for Obesity in Prader Willi Syndrome: Systematic Review and Meta-Analysis’, published in SOARD, by researchers from Drexel University College of Medicine, Philadelphia, PA.

The authors explained that Prader-Willi Syndrome (PWS) is a genetic disorder from a lack of expression of genes on the paternally inherited chromosome 15q11.2-q13 region resulting in an accumulation of numerous endocrine abnormalities. Although the exact mechanism/s driving obesity in PWS is unknown numerous hormones are believed to play a role, such as increased ghrelin and a deficiency in growth hormone.

Despite the evidence of MBS demonstrating long-term weight loss, surgery has been poorly studied in the PWS population. As a result, the investigators conducted a systematic review and meta-analysis to determine the change in BMI after LSG, GB and BPD-DS. The literature search resulted in 22 papers data met criteria for the meta-analysis (n=67 individuals with PWS that had MBS and met criteria for inclusion into the meta-analysis).


The age range of the patients with PWS included in the meta-analysis at the time of MBS was 5 to 40 years old with a majority (52%, 33 patients, 56% males) being 17 years or younger. The three groups were statistically different in their baseline age. The average age of the LSG group was 12.8, GB group was 18.4, and the BPD group was 21.4 years (p-value <0.01). The researchers found that there was no significant difference in the baseline BMI between the three groups (p=0.12). The ethnicity and race of the patients with PWS were not recorded in the majority of the papers.

At the one year follow up period individuals with PWS had a reduction of 14.9 kg/m2, 11.4 kg/m2, 15.5 kg/m2 for the LSG, GB, and BPD groups. The LSG group (n=26) had a significant reduction in BMI through three years of follow up with a reduction of 15.2kg/m2 from baseline at three years (p=0.002). The gastric bypass group (n=10) had the fewest number of patients with PWS and had significant reduction in BMI up to two years of follow up with a reduction of 12.1 (p=0.001). The BPD-DS group (n=28) had the most patients that followed up past five years and had significant reduction in BMI up until seven years of follow-up with an average reduction of 10.7 (=0.02) at year seven.

Although the statistical analysis was limited by the loss of patients in the follow-up years, the BPD-DS group seemed to confer the most weight loss in the long term with a reduction in BMI of 10.7 and 10.9 kg/m2 at years seven (n=10) and ten (n=6). While the LSG group had weight gain with an increase in BMI of 0.3 and 0.8 kg/m2 at years seven (n=2) and ten (n=2) (Figure 1).

Figure 1: Average BMI of LSG, BPD, and GB groups. There is no statistical difference between the baseline BMI or BMI at any follow up period between any of the three groups. Statistical analysis of the BMI between groups is severely limited by the small sample sizes within the meta-analysis.

There was no surgical mortality or revisions in any of the groups in the meta-analysis within one year of any MBS operation. In the BPD group, 3 of 28 had revisions between two and four years follow up. One of these revisions occurred at 2 years for excessive weight loss, and two for recurrence of severe obesity at 2 and 4 years. No other revisions were reported. In addition, there were no surgical complications reported in the LSG or GB groups. The BPD group (n=28) had three cases of ventral hernias most likely related to open operations and one small bowel obstruction.

The researchers highlighted the poor quality and paucity of the articles in MBS as treatment for severe obesity in PWS patients. Therefore, they encouraged data collection to track long-term outcomes following MBS for patients with PWS, as although there are registries for PWS such as the Italian National Registry and the Global Prader-Willi Syndrome Registry, “to our knowledge there is no registry that tracks long-term outcomes following MBS for patients with PWS…it may indeed be time to take a new look at MBS for patients with PWS”, given the weight loss resulting from MBS in this group of patients.

Further information

To access this paper, please click here


bottom of page