Conflict of interest

Takashi Murata has received honoraria from Eli Lilly Japan, Sanofi, Kowa Pharmaceutical, Novo Nordisk, Kyowa Kirin, and Takeda Pharmaceutical; and grants from Sanofi and Kowa Pharmaceutical. Lise Lotte N. Husemoen and Satoko Nemoto are employed by Novo Nordisk. Munehide Matsuhisa has received honoraria from Sanofi, Takeda Pharmaceutical, Eli Lilly Japan, Mitsubishi Tanabe Pharma Corporation, Astellas Pharma, Novo Nordisk, Orizuru Therapeutics, Sumitomo Pharma, Abbott Japan, and MSD; research funding from Sysmex, Nissui, and Tokushima Data Service; and subsidies or donations from Astellas Pharma, Nippon Boehringer Ingelheim, Daiichi Sankyo, Mitsubishi Tanabe Pharma, Novartis, Sanofi, Novo Nordisk, Takeda Pharmaceutical, MSD, and Ono Pharmaceutical.

Ethical approval

The study was conducted according to requirements of the revised Declaration of Helsinki, the Guidelines for Good Pharmacoepidemiology Practices, the Japanese Ministry of Health, Labour and Welfare Notification No. 171, “Ordinance Concerning the Standards for Conducting Post-Marketing Surveys and Studies on Drugs”, and the Japanese Ministry of Health, Labour and Welfare Notification No. 135, “Ordinance Concerning the Standards for Post-Marketing Safety Management of Drugs, Medical Devices, Cosmetics and Medical Devices” (GVP; issued 22 September 2004). The protocol and any amendments were approved at each investigator site, as required locally. All procedures followed were in accordance with the ethical standards of the responsible committee on human experimentation (institutional and national) and/or with the Helsinki Declaration of 1964 and later versions.

Informed consent

All participants or legally acceptable representatives (for children) provided written informed consent. Prior to study-related activities and commencement of degludec, the physician had to provide written and oral study information to the patient/representative to be read and understood.

Approval date of registry and the registration no. of the study/trial

This study was pre-registered to ensure transparency and minimize selective reporting bias. The first submitted date was 07 November 2013 and the first posted date was 14 November 2013. The ClinicalTrials.gov registration number is NCT01984372.

Animal studies

N/A.