Aim: To examine trends of second-line glucose-lowering therapies among patients with type 2 diabetes (T2D) initiating first-line metformin in the United States and the United Kingdom, overall and by subgroups of cardiovascular disease (CVD) and calendar time.
Methods: Using the US Optum Clinformatics and the UK Clinical Practice Research Datalink, we identified adults with T2D who initiated first-line metformin or sulphonylurea monotherapy, separately, from 2013 to 2019. Within both cohorts, we identified patterns of second-line medications through June 2021. We stratified patterns by CVD and calendar time to investigate the impact of rapidly evolving treatment guidelines.
Results: We identified 148 511 and 169 316 patients initiating treatment with metformin monotherapy in the United States and the United Kingdom, respectively. Throughout the study period, sulphonylureas and dipeptidyl peptidase-4 inhibitors were the most frequently initiated second-line medications in the United States (43.4% and 18.2%, respectively) and the United Kingdom (42.5% and 35.8%, respectively). After 2018, sodium-glucose co-transporter 2 inhibitors and glucagon-like peptide-1 receptor agonists were more commonly used as second-line agents in the United States and the United Kingdom, although these agents were not preferentially prescribed among patients with CVD. Initiation of first-line sulphonylureas was much less common, and most sulphonylurea initiators had metformin added as the second-line agent.
Conclusions: This international cohort study shows that sulphonylureas remain the most common second-line medications prescribed following metformin in both the United States and the United Kingdom. Despite recommendations, the use of newer glucose-lowering therapies with cardiovascular benefits remains low.
Keywords: cardiovascular disease; cohort study; drug utilization; glucose-lowering medications; pharmacoepidemiology; type 2 diabetes.
© 2023 John Wiley & Sons Ltd.