Cost sharing and branded antidepressant initiation among patients treated with generics

To determine the relationship between consumer cost sharing for branded antidepressants and the initiation of branded therapy among patients with major depressive disorder (MDD) filling a prescription for generic MDD medication.

Retrospective cross-sectional analyses.

Patients aged 18 to 64 years with MDD who filled a generic antidepressant were identified in commercial claims data for 2012 to 2014. For each year-specific analysis, an average cost-sharing index for branded antidepressants at the level of the plan was computed. Multivariable models were used to estimate the relationship between plan-level cost sharing for branded antidepressant medications and the filling of branded prescriptions, with demographic and clinical variables as covariates.

For patients with MDD filling a generic prescription, increases in branded cost sharing were associated with significant decreases in the likelihood of filling a branded antidepressant in each year (P <.001). Results in 2012 imply that a shift from the 0th to 90th percentile in the branded cost-sharing index corresponded with a 9.5% decrease in the relative likelihood of a branded fill among patients receiving a generic antidepressant. The corresponding figures for 2013 and 2014 were 9.3% and 3.5%, respectively.

In MDD, patients and clinicians who dutifully adhere to guidelines requiring a trial of first-line medication may ultimately require therapy with alternate agents to achieve adequate disease control. A "reward the good soldier" benefit design would lower cost sharing for higher-tier evidence-based therapies when clinically indicated. Results suggest that narrowing the gap in cost sharing between branded and generic medications following a trial of a generic agent might improve access to second-line treatment in MDD.