Enrollment in high-deductible health plans is increasing out-of-pocket spending. But innovative plans that pair deductibles with value-based insurance designs can help preserve low-cost access to high-value treatments for patients by aligning coverage with clinical value. Among adults in high-deductible health plans who were prescribed medications for chronic conditions, we examined what impact a value-based pharmacy benefit that offered free chronic disease medications had on medication adherence. Overall, we found that the value-based plan offset reductions in medication adherence associated with switching to a deductible plan. The value-based plan appeared particularly beneficial for patients who started with low levels of medication adherence. Patients with additional clinical complexity or vulnerable populations living in neighborhoods with lower socioeconomic status, however, did not show adherence improvements and might not be taking advantage of value-based insurance design provisions. Additional efforts may be needed to educate patients about their nuanced benefit plans to help overcome initial confusion about these complex plans.