Impact of a combined value-based insurance design and medication therapy management program on diabetes medication adherence

Abstract

BACKGROUND: Value-based insurance design (VBID) waives or reduces prescription copayments in order to decrease member cost barriers to refilling medications. Medication therapy management (MTM) is a member clinical intervention designed to reinforce members' knowledge of their medications, which addresses barriers to medication adherence. Both methods have been shown to increase adherence in members, particularly when used in combination. To date, studies of such combined programs have often been completed within integrated health systems but have rarely included control populations. OBJECTIVE: To determine the effect of a combined VBID and MTM program on key medication adherence metrics among diabetic members of a large employer group in the Midwest. METHODS: A retrospective pre/post longitudinal analysis of pharmacy claims data was performed for 77 participants in a combined VBID/MTM program and 77 eligible nonparticipants, matched by the baseline adherence metrics of proportion of days covered (PDC) and number of days without therapy, also known as gaps in therapy (GIT). Oral antidiabetic medication adherence and cost-related outcomes for all pharmacy claims were evaluated within and between groups over a 6-month period. Post hoc analyses were performed to investigate the effect of the intervention by gender and among a less adherent subpopulation of participants with a PDC of < 100% at baseline. RESULTS: Introduction of the intervention resulted in a nonsignificant increase in PDC from 92.9% to 95.4%, in contrast to a nonsignificant decrease from 92.8% to 91.7% in the comparison group. GIT underwent a nonsignificant decrease of 2.83 days during intervention, while nonsignificantly increasing 2.82 days in the comparators. Pharmacy claims costs paid by the plan per member per 6-month period significantly increased in the intervention group from $1,991.23 to $3,092.74, compared with a nonsignificant increase from $1,402.21 to $1,645.68 in the comparison group. Among the less-adherent subpopulation, PDC increased significantly after intervention from 84.7% to 93.1% compared with a nonsignificant increase from 84.6% to 89.0% among nonparticipants. A significant 10.69-day decrease in GIT was also observed among nonadherent participants compared with a nonsignificant 3.59-day decrease among nonparticipants. Female participants experienced a significant PDC increase from 91.5% to 96.8% and a GIT decrease of 7.32 days, while male participants did not change significantly. CONCLUSIONS: While statistically significant improvements to adherence were not observed among this population of members who were highly adherent at baseline, improvement trends and subgroup analyses demonstrated that the combined VBD/MTM program may have the potential to influence member behavior in employer groups. Larger, longer-term studies are needed to confirm this potential. Additional benefit may be realized by targeting members with lower adherence metrics at baseline and examining potential cost savings associated with medical outcomes.