Adaptation of the By-Band randomized controlled trial to By-Band-Sleeve to include a new intervention and to maintain relevance of the study to practice

Recruitment into randomised controlled trials (RCTs) in surgery can be threatened if new interventions available outside the trial compete with those being evaluated. Adapting the trial to include the new intervention may overcome this issue yet this is not often done in surgery. This paper describes the challenges, rationale and methods for adapting an RCT to include a new intervention.
The By-Band Study was designed in the UK in 2009/10 to compare the effectiveness of laparoscopic adjustable gastric Band and Roux-en-Y gastric Bypass for severe obesity. It contained a pilot phase to establish whether recruitment was possible and the grant proposal specified that an adaptation to include Sleeve gastrectomy would be considered if practice changed and recruitment successful. Information on changing obesity surgery practice, updated evidence and expert opinion about trial design was used to inform the adaptation.
The pilot phase recruited over 13 months in 2013/14 and randomised 80 (79 anticipated) patients. During this time major changes in obesity practice in the UK were observed, with Band reducing from 35% to 24% and Sleeve increasing from 8% to 29%. The evidence-base had not changed markedly. The British Obesity and Metabolic Surgical Society and study oversight committees supported an adaptation to include Sleeve and a proposal to do so was approved by the funder.
Adaptation of a two-group surgical RCT can allow evaluation of a third procedure and keep the RCT relevant to practice. It also optimises the use of existing trial infrastructure to answer an additional important research question.