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Evidence section

Bariatric surgery studies

Reviewed and signedLast updated 2026-09-18Reviewed by two pharmacists registered in British Columbia, 2026-09-18

Two pharmacists registered and practising in British Columbia read this page against the study pages and papers it lists and signed it. Their names are withheld from the site and held on file; their registration is confirmed on request.

Bariatric surgery has the longest follow-up of any weight-management treatment. The Swedish Obese Subjects study followed people for more than ten years and reported on death rates, heart events, diabetes and life expectancy. STAMPEDE randomized people with type 2 diabetes to surgery or intensive medical therapy and reported at one, three and five years. This hub explains those papers and what an observational study can and cannot show.

Studies in this section (7)

Ten years after weight-loss surgery: the Swedish Obese Subjects study

Plain-language summary of the Swedish Obese Subjects study on weight and health risks 10 years after bariatric surgery, written for Canadian readers.

2004Reviewed and signed

Bariatric surgery and death rates: the Swedish Obese Subjects study

What the Swedish Obese Subjects study found about deaths over 10.9 years after bariatric surgery versus conventional care, explained for Canadian readers.

2007Reviewed and signed

Bariatric surgery and heart events: the Swedish Obese Subjects study

Swedish Obese Subjects study results on heart attacks, strokes and cardiovascular deaths after bariatric surgery, explained for Canadian readers.

2012Reviewed and signed

STAMPEDE: bariatric surgery versus medical therapy for type 2 diabetes

The STAMPEDE trial compared bariatric surgery with intensive medical therapy for type 2 diabetes at one year. Plain-language summary for Canadian readers.

2012Reviewed and signed

STAMPEDE at three years: surgery versus medical therapy for diabetes

Three-year results of the STAMPEDE trial comparing bariatric surgery with intensive medical therapy for type 2 diabetes, explained for Canadian readers.

2014Reviewed and signed

STAMPEDE at five years: surgery versus medical therapy for diabetes

Five-year STAMPEDE results on bariatric surgery versus medical therapy for type 2 diabetes, including the missing-data caveat, for Canadian readers.

2017Reviewed and signed

Life expectancy after surgery: the Swedish Obese Subjects study

What the Swedish Obese Subjects study found about life expectancy and deaths more than 20 years after bariatric surgery, explained for Canadian readers.

2020Reviewed and signed

Other evidence sections

Semaglutide studies explainedTirzepatide studies explainedEmerging weight-management medicinesLiraglutide, naltrexone-bupropion and orlistat studiesSetmelanotide and rare genetic obesityWhat happens when weight-management medicines are stoppedLifestyle programs, dietitians and diabetes preventionSide effects and safety studiesGLP-1 medicines and pregnancyHow people use GLP-1 medicines outside trialsCanadian guidelines and cost studiesEating disorders and behavioural weight management

How to read these pages

Every page in this section explains one published study. The numbers are reported as the researchers published them, with a link to the paper on PubMed. Pages say what a study cannot tell you and never rank one medicine against another. They are education, not medical advice. For how a medicine is used and paid for in Canada, see medicines, public drug coverage by province and compare services.

Reviewed and signed by two pharmacists registered in British Columbia, 2026-09-18.