Patients with type 2 diabetes are least likely to adhere to the most commonly prescribed medication for their disease, potentially because of its adverse-event profile, suggests new research published online in Diabetes, Obesity and Metabolism.

A review of almost 50 studies showed that patients did not take 30% of prescribed doses of metformin, compared with 23% of doses of sulfonylureas, such as gliclazide, and 20% of thiazolidinediones, such as pioglitazone. Newer dipeptidyl peptidase-4 (DPP-4) inhibitors, or gliptins, had higher adherence rates, with patients not taking just 10% to 20% of doses. Researchers noted that compared with metformin, adherence was better with sulfonylureas, at a mean difference in adherence of 10.6% across five studies, and with thiazolidinediones, at a mean difference of 11.3% across six studies.