DPP4 and thyroid cancer: This approach mainly accounted for the possibility that a proportion of patients could have switched from DPP4 inhibitors to GLP1 receptor agonists during follow-up (a potential thyroid cancer risk with GLP1 receptor agonists could spill over into the group classified as receiving DPP4 inhibitors according to the intention-to-treat definition for drug use, which might lead to an underestimation of thyroid cancer risk with GLP1 receptor agonists).