Different reduction in cardiovascular risk after different bariatric procedures

In her PhD thesis, Hilde Risstad has compared the effects of different procedures of bariatric surgery in patients with extremely high body mass index.


  1. Compared to gastric bypass, duodenal switch resulted in greater 5-year weight reduction, as well as improved blood lipids and glucose levels.
  2. The reductions in cholesterol and blood sugar levels up to two years after surgery were greater following distal than standard gastric bypass. However, there was no difference in weight reduction.
  3. Adverse effects were more common following duodenal switch and distal gastric bypass compared to standard gastric bypass.


Thesis: Comparison of variants of gastric bypass and duodenal switch as treatment for severe obisity (BMI 50-60) in randomized controlled trials.
Candidate: Hilde Risstad
Time: November 17, 2017 at 13:15
Place: Oslo University Hospital, Ullevål, The Cancer Centre (Building 11): Ground Floot Auditorium
Link to university website (in Norwegian)


Hilde Risstad and coworkers included 20–60-year-old patients with a body mass index of 50–60 in two randomized controlled trials. The first study compared the effect of the bariatric procedures of Roux-en-Y gastric bypass and biliopancreatic diversion with duodenal switch, whereas the other study focused on standard or distal Roux-en-Y gastric bypass. 

(1) 5-year reduction in BMI following duodenal switch was 22.1. 5-year reduction in BMI following gastric bypass was 13.6. Duodenal switch also reduced total cholesterol, LDL cholesterol, triglycerides and fasting glucose more than gastric bypass. Changes in blood pressure, diabetes and metabolic syndrome remission rates were similar between the two groups

However, patients in the duodenal switch group had significantly more hospital admissions during follow-up, and also more surgery related to the initial procedure. They also had lower  levels of vitamins A and D, and more gastrointestinal adverse events. 55 out of the 60 included patients completed the five year follow-up after duodenal switch or gastric bypass.

(3) Bile acid concentrations increased in both groups, but more following duodenal switch than gastric bypass. Higher bile acid levels five years after surgery were related to lower levels of total cholesterol.

(2) Contrary to the hypothesis, distal gastric bypass did not reduce weight more than standard gastric bypass. The follow-up time in this randomized study was two years, and 113 patients were included. Mean reduction in BMI was 17–18 in both groups.

Total and LDL cholesterol, as well as fasting glucose, decresead more following distal gastric bypass. However, loose stools and secondary hyperparathyroidism were also more frequent after the distal procedure.


(1) Risstad, H., Søvik, T. T., Aasheim, E. T., Fagerland, M. W., Olsén, M. F., Kristinsson, J. A., le Roux, C. W. Bøhmer, T., Birkeland, K. I., Mala, T, & Olbers, T. (2015). Five-year outcomes after laparoscopic gastric bypass and laparoscopic duodenal switch in patients with body mass index of 50 to 60: a randomized clinical trialJAMA surgery150(4), 352-361.

(2) Risstad, H., Svanevik, M., Kristinsson, J. A., Hjelmesæth, J., Aasheim, E. T., Hofsø, D., Søvik, T. E., Karlsen, T.-I., Fagerland, M. W., Sandbu, R., & Mala, T. (2016). Standard vs distal Roux-en-Y gastric bypass in patients with body mass index 50 to 60: A double-blind, randomized clinical trialJAMA surgery151(12), 1146-1155.

(3) Risstad, H., Kristinsson, J. A., Fagerland, M. W., le Roux, C. W., Birkeland, K. I., Gulseth, H. L., Thorsby, P. M., Vincent, R- P., Engström, M., Olbers, T., & Mala, T. (2017). Bile acid profiles over 5 years following gastric bypass and duodenal switch–Results from a randomized clinical trialSurgery for Obesity and Related Diseases.

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