Definitions of medications used in the present study

Classification of all drugs involved in the study was performed using the WHO Collaborating Centre for Drug Statistics and Statistics Methodology anatomical therapeutic chemical (ATC) index 2014. Drugs with an ATC index of A10B were classed as OAD medication, with the exception of injectables such as human insulin and licensed glucagon-like peptide-1 agonists (A10BX04, A10BX07, and A10BX10). Long-acting insulins (A10AE) and intermediate-acting NPH insulins (A10AC01) were classed as BIs, while short-acting insulins (A10AB) were not included in this category. Concomitant medications, for example, β-blockers, were identified by any ATC indices other than A10. Where identical medication usage was documented at an interval of <6 months, records were merged into one episode. Missing records at the end of treatment were artificially imputed using the mean time periods observed (BI 0.546 years; OADo 0.467 years) for all recorded patients diagnosed with T2DM.