INS and diabetes mellitus: Metformin is a first-line treatment for early-stage T2D, and increasing severity of DM over time often requires a switch to other hypoglycaemic agents or insulin.32 To avoid an overestimation of the association between metformin and LC survival, comparing metformin users with non-users of any anti-diabetic medication has been advocated.6,7,13,20–24,34 This is also supported by our findings indicating that especially insulin users had a worse survival than the non-anti-diabetic users (Table S4).