The researchers acknowledge several limitations to their analysis:
• Lack of data on long-term durability of the treatment, as included trials ranged in duration from 12 weeks to 36 weeks. • There were study features that carry potential risk of bias such as open-label design and pharmaceutical industry funding.• Long-term safety and side-effects of GLP-1 agonists have not been established.• The ideal timing for beginning this treatment in the clinical course of the disease is unknown.
They note that combination preparations, in which the relative proportion of GLP-1 agonist to basal insulin is fixed, are in development to enable convenient administration of both drugs with one subcutaneous injection. Although further studies are needed to establish the optimal approach to the application of this treatment in practice, they suggest that their findings lend support to the use of GLP-1 agonists in combination with basal insulin in the clinical management of patients with type 2 diabetes.
According to a Comment article, “the combination of GLP-1 agonist and basal insulin has finally arrived as a more powerful and safer alternative to insulin in the management of type 2 diabetes.” It notes the lack of adequate trials to address whether shorter-acting GLP-1 agonists provide unique advantages over long-acting GLP-1 agonists combined with basal insulin, but the differences are likely to be small. It suggests that fixed-dose combinations of a GLP-1 agonist and basal insulin in development will be welcomed in view of their convenience and efficacy. The major barrier to widespread adoption of these treatments is cost—both GLP-1 agonists and insulin analogues are among the most expensive in diabetes care.