Effect of Patient Notification of Formulary Change on Formulary Adherence

OBJECTIVES: To evaluate the impact of patient notification of impending formulary changes on formulary adherence. METHODS: This pilot program in a large, Midwest-based health insurer utilized a randomized controlled trial research design. A list of 30 chronic-use medications that were to change formulary status were selected for the pilot. A review of adjudicated pharmacy claims records was performed to identify patients receiving one or more of the formulary change medications on the list. Members of 112 individual health plans of this large health insurer, all of whom were subject to the same drug formulary, were randomized to either the intervention (letter) or control arm. Patients in the intervention arm were sent a targeted communication that described the patients formulary change medication(s) and provided therapeutic option(s) for the formulary change medication(s). Pharmacy claims for patients in both arms were examined at 110 days after the date of the mailing to determine if there was a switch to a formulary alternative. Multivariate regression modeling was performed to adjust for baseline differences between the arms. RESULTS: A total of 7,247 unique formulary change medication regimens were identified (3,817 in the control arm and 3,430 in the letter arm) for 6,518 subjects (3,387 in the control arm and 3,131 in the letter arm). A higher proportion of formulary change medication regimens in the intervention arm were switched to a formulary alternative compared with the control arm (19.2% vs. 12.0%, P less than 0.001). After adjustment for baseline differences, regression modeling indicated that subjects in the intervention arm were 1.33 times more likely to switch to a formulary alternative (P less than 0.001). CONCLUSIONS: A letter-based, formulary change notification program is a pragmatic and effective strategy to increase drug formulary adherence. Such a program does not restrict access to medications but, rather, provides education and personalized information that may allow patients to participate more actively in their pharmacotherapy decision making.