We assumed that most of the insulin users in our study had type 1 diabetes, because we excluded patients who ever used oral blood glucose lowering medicines, had cystic fibrosis or malignancies in the year prior to the index date, and other types of diabetes needing insulin (e.g. Latent autoimmune diabetes in the adults (LADA) and mitochondrial diabetes, etc.)have low prevalences compared with type 1 diabetes [34], [35]. Here, INS is linked to diabetes mellitus.