Copay assistance use and prescription abandonment across race, ethnicity, or household income levels for select rheumatoid arthritis and oral oncolytic medicines.

Disparities in prescription abandonment may exacerbate health inequities. Whether copay assistance is associated with changes in prescription abandonment across different patient groups is unknown. To assess disparities in copay assistance use; prescription abandonment across race, ethnicity, or income; and association of copay use with prescription abandonment and whether it differs across race, ethnicity, or household income.