Background: The difference between the costs of the newer and older glucose-lowering drugs (GLMs) has been steadily increasing since 2010. In 2018, newer drugs cost 8-12 times more than older drugs (except for insulin). This study aimed to understand how the cost change influenced the cost-effectiveness of the newer GLMs.
Methods: Based on our previous literature review on US-based cost-effectiveness studies comparing newer (i.e. dipeptidyl peptidase-4 inhibitors (DPP4), glucagon-like peptide 1 receptor agonists (GLP1-RA), and sodium-glucose transport protein 2 inhibitors) with older GLMs, we identified 12 studies that reported the cost-effectiveness of newer drugs based on drug costs estimated before 2010. We updated the corresponding cost-effectiveness of each study by replacing the old cost estimates with 2018 estimates from the 2018 IBM MarketScan Commercial Claims Databases. The time window and willingness to pay threshold were consistent with the original studies.
Results: Only 8% of the original studies suggested that the older drugs were cost-effective. However, 58% of studies were in favor of the older drugs after the cost update. Among the four studies comparing newer drugs with thiazolidinediones, all the original results favored newer drugs. However, all studies suggested thiazolidinedione to be cost-effective in the updated analysis. For the four studies comparing newer drugs with sulfonylureas, two studies suggested the sulfonylureas to be cost-effective after the cost update. All four studies suggested newer drugs to be cost-effective when compared with insulin in the original study. Only 1 flipped its conclusion when 2018 costs were used. Our sensitivity analysis shows that our results are robust under a 30% rebate.
Conclusion: Significant changes in the cost of GLMs have impacted the economic value of different GLM classes substantially. More cost-effectiveness analyses are warranted to support the drug choice in T2DM management.
Keywords: Cost-effectiveness; DPP4; GLP-1 receptor agonist; SGLT2 inhibitors; newer glucose-lowering drug.