Competing interests: The BMJ has judged that there are no disqualifying financial ties to commercial companies. The authors declare the following other interests: DL reports no relevant interests. TO reports that she has served on a Physician Advisory Board for Dexcom, served as a consultant for Cecilia Health, DiabetesWise, and received an investigator-initiated award from Abbott Diabetes. BW reports that he has received research funding from Medtronic, Dexcom, and iSENS.