The comparative effectiveness of various bariatric procedures on remission of type 2 diabetes remains debated. We aimed to compare the two most commonly used procedures, hypothesising higher remission rates of diabetes after gastric bypass than after sleeve gastrectomy. Methods:The Oseberg study is an ongoing triple-blind, randomised, single-centre trial taking place at Vestfold Hospital Trust, Norway. Adult patients with type 2 diabetes and obesity were randomly assigned (1:1) to receive either gastric bypass or sleeve gastrectomy. Randomisation was performed with a computerised random number generator using block sizes of 10. Treatment allocation was concealed using sealed opaque envelopes, and was masked from participants, study personnel and outcome assessors. Primary outcomes were, first, the proportion of participants with complete remission of diabetes; glycated haemoglobin 6•0% (42 mmol/mol) or less with no diabetes medication, and, second, beta-cell function modelled from an intravenous glucose tolerance test at one year. Analyses were performed according to intention-to-treat and per-protocol principles. The trial is registered at ClinicalTrials.gov with identifier: NCT01778738.

Clinicaltrials.gov Identifier: NCT00821197.