Obesity increases the risk for diseases and early death. In Norway bariatric surgery is offered to persons with morbid obesity (body mass index (BMI) ≥ 35 kg/m 2 with at least one obesity related comorbidity or KMI ≥ 40 kg/m 2 ) when other treatments have been ineffective. We have summarized research of long-term effects after bariatric surgery compared with non-surgical treatment in persons with BMI ≥ 30 kg/m 2 . Based on the results from eight randomized controlled studies with follow-up of up to two years and eight prospective controlled studies with follow-up for up to 20 years, we conclude that:
It is unclear whether bariatric surgery reduces total mortality and cardiovascular deaths from myocardial infarction and stroke. The quality of evidence is low to very low.
Bariatric surgery may induce a significant and persistent weight loss of 15-20 % for up to 10 years, depending on surgery type. The quality of evidence is moderate.
Bariatric surgery may reduce prevalence of type 2 diabetes mellitus and remission of hypertension. The quality of evidence is moderate for diabetes and low for hypertension.
Bariatric surgery may increase quality of life assessed as physical component scores. The quality of evidence is low.
It is unclear whether bariatric surgery has effect on symptoms of anxiety and depression. The quality of evidence is very low.
Prevalence of adverse events were unsystematically and inadequately reported.
Bariatric surgery had a positive effect on several outcomes, but effect size may vary based on type of surgery and treatment in the non-surgical groups. The largest and most important weakness is the lack of large studies of good quality with long-term follow-up.
Keywords: bariatric surgery; gastric bypass; gastroplasty.
Copyright ©2014 by The Norwegian Institute of Public Health (NIPH).