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Effect of Roux-en-Y gastric bypass surgery on diabetes remission and complications in individuals with type 2 diabetes: a Danish population-based matched cohort study

  • Lene R. MadsenEmail author
  • Lisbeth M. Baggesen
  • Bjørn Richelsen
  • Reimar W. Thomsen



The aim of this study was to examine the effect of Roux-en-Y gastric bypass (RYGB) surgery on diabetes remission, subsequent diabetes relapse and micro- and macrovascular complications in individuals with type 2 diabetes and obesity (BMI >35 kg/m2) in a real-world setting.


This was a population-based cohort study of 1111 individuals with type 2 diabetes treated by RYGB at hospitals in Northern Denmark (2006–2015), and 1074 matched non-operated individuals with type 2 diabetes. Diabetes remission was defined as no glucose-lowering drug use with HbA1c <48 mmol/mol (<6.5%), or metformin monotherapy with HbA1c <42 mmol/mol (<6.0%). Data on complications were ascertained from medical registries with complete follow-up.


At 1 year of follow-up, 74% of the cohort treated by RYGB experienced diabetes remission, while 27% had relapsed after 5 years. Predictors of non-remission were age >50 years, diabetes duration >5 years, use of glucose-lowering drugs other than metformin, and baseline HbA1c >53 mmol/mol (>7.0%). Compared with the non-operated cohort using adjusted Cox regression (5.3 years follow-up), the cohort treated by RYGB had 47% lower risk of microvascular complications (HR 0.53 [95% CI 0.38, 0.73]) and a statistically non-significant 24% lower risk of macrovascular complications (HR 0.76 [95% CI 0.49, 1.18]). Diabetes remission vs non-remission at 1 year was associated with reduced HR of 0.43 (95% CI 0.25, 0.72) for microvascular complications and with HR of 0.76 (95% CI 0.40, 1.45) for macrovascular complications.


In routine clinical care, three out of four individuals with type 2 diabetes and obesity treated by RYGB experienced diabetes remission after 1 year, whereas 27% of these individuals had relapsed at 5 years follow-up. RYGB was associated with substantially decreased risk of microvascular complications and non-significantly fewer macrovascular complications, with early diabetes remission as a clear predictor of reduced microvascular complications.


Diabetes remission Gastric bypass Macrovascular complications Microvascular complications Population-based study Roux-en-Y gastric bypass Type 2 diabetes 



Charlson comorbidity index


Danish Civil Registration System


Danish National Health Service Prescription Database


Danish National Patients Registry


Glucose-lowering drug


Interquartile range


Incidence rate


Incidence rate ratio


Roux-en-Y gastric bypass


Swedish Obese Subjects



The Department of Clinical Epidemiology is a member of the Danish Centre for Strategic Research in Type 2 Diabetes (DD2), supported by the Danish Agency for Science (09-067009, 09-075724), the Danish Health and Medicines Authority, the Danish Diabetes Association and an unrestricted donation from Novo Nordisk A/S. Project partners are listed at The Department of Clinical Epidemiology participates in the International Diabetic Neuropathy Consortium (IDNC) research programme, which is supported by a Novo Nordisk Foundation Challenge programme grant (NNF14SA000 6).

Contribution statement

LRM designed the study, researched the data and drafted the manuscript. LMB designed the study and performed the statistical analysis. BR and RWT designed the study and revised the manuscript critically. All authors contributed to the discussion and approved the final manuscript. LRM is the guarantor for the content of this article.


LRM is affiliated to the Danish Diabetes Academy funded by the Novo Nordisk Foundation. The study was funded by the Health Research Fund of Central Denmark, the Novo Nordisk Foundation and the A. P. Møller Foundation. The study sponsors were not involved in the design of the study, the collection, analysis and interpretation of data, writing the report or the decision to submit the report for publication.

Duality of interest

The authors declare that there is no duality of interest associated with this manuscript.

Supplementary material

125_2019_4816_MOESM1_ESM.pdf (401 kb)
ESM (PDF 401 kb)


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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  • Lene R. Madsen
    • 1
    Email author
  • Lisbeth M. Baggesen
    • 2
  • Bjørn Richelsen
    • 1
  • Reimar W. Thomsen
    • 2
  1. 1.Department of Endocrinology and Internal MedicineAarhus University HospitalAarhus NDenmark
  2. 2.Department of Clinical EpidemiologyAarhus University HospitalAarhusDenmark

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