Factors That Influence Patient Response to Requests to Change to a Unified Restrictive Formulary

OBJECTIVE:  To determine factors that influence patient willingness to accept a medication change to a unified, restrictive formulary. DESIGN:  Prospective cohort study. SETTING:  University‐affiliated hospital‐based primary care internal medicine practice. PATIENTS/PARTICIPANTS:  Two hundred ninety‐seven members of a managed care plan who had received a prescription for a nonformulary medication in the previous 4 months and whose primary care physician approved a conversion to a formulary medication. INTERVENTIONS:  Clinical nurses invited patients to change to a formulary medication at the time of a telephone refill request based on a standard script. MEASUREMENTS AND MAIN RESULTS:  The overall conversion rate to the formulary medication was 59.8%. Seventy‐four percent of patients who requested a refill by telephone converted to the formulary (odds ratio [OR], 2.24; 95% confidence interval [CI], 1.02 to 4.72). Patient age (OR, 1.03; CI, 1.01 to 1.05) and male gender (OR, 2.00; CI, 1.09 to 3.67) were each significant correlates of conversion. After adjustment in a multivariable model, only telephone refill request (adjusted OR, 2.31; CI, 1.07 to 4.97) and age (adjusted OR, 1.03; CI, 1.01 to 1.06) remained significant. Among the patients who made a telephone refill request, those who converted were more likely to completely trust their physician's judgment ( P = .04) and to trust their physician to put their health over cost concerns ( P = .05). Formulary conversion reduced costs beginning 3 months after the conversion date. CONCLUSIONS:  A protocol for encouraging conversion to a unified formulary at the point of a telephone refill request increases formulary compliance rates and reduces medication costs. Patients who decline to convert medications are less likely to trust their physician.