Formularies Should Reflect How Copays Impact Diabetes Drug Adherence

A study presented at the American Diabetes Association’s 77th Scientific Sessions found that the impact diabetes drug copays have on patients vary widely between generic and branded products.

“Prior studies that have shown that higher copay was associated with lower medication adherence were mostly conducted in younger commercially insured type 2 diabetes patients,” Manjiri Pawaskar, PhD, director of the Center for Observational and Real-World Evidence at Merck, and colleagues wrote. “This relationship is unclear in elderly patients. The current study examined this association in Medicare patients with type 2 diabetes using branded or generic non-insulin antihyperglycemic agents.”

The researchers conducted a retroactive study of Medicare patients older than 65 years with type 2 diabetes. They examined 28,656 patients who used branded noninsulin anti-hyperglycemic agents and 131,594 patients who used generic versions. 

Study resulted showed that the average copay for a branded product was $40 compared with $5 for generic versions. The researchers found that higher copays were associated with lower adherence and higher discontinuation among patients taking branded products. They noted that a patient with a $60 copay for a branded product was 71% less ikely to be adherent and 1.5 times likely to discontinue when compared with a patinent taking a branded product with a less than $10 copay.

Notably, this association was not found among patients taking generic versions.

The researchers noted that their results should impact the decisions payers make when determining how drugs are covered on formularies.

“This study suggests that the impact of drug copay on adherence and discontinuation varies considerably for branded vs generic noninsulin antihyperglycemic agents among Medicare patients,” Dr Pawaskar and colleagues concluded. “Payers should take into consideration these findings while making formulary decisions.” —David Costill