Value-based insurance design yields near- and long-term improvements in medication adherence.

Key findings. (1) Value-based insurance design (VBID) improves medication adherence by 1 to 3 percent in the first year after implementation; (2) Improvements in adherence were sustained and amplified in the second year post-implementation, ranging from 2 to 5 percent; (3) Adherence improvements varied ac­cording to VBID participants' baseline adherence, with greatest improve­ments evident in those with poorer baseline adherence