The Nudging Effect of a Reminder Letter to Reduce Duplicated Medications: A Randomized Controlled Trial.

Background: The increasing trend of multiple chronic conditions across the world has worsened the problem of medication duplication in health care systems without gatekeeping or referral requirement. Thus, to overcome this problem, a reminder letter has been developed in Taiwan to nudge patients to engage in medication management.

Objective: To evaluate the effect of reminder letter on reducing duplicated medications.

Research design: A 2-arm randomized controlled trial design.

Subjects: Patients with duplicated medications in the first quarter of 2019.

Measures: The Taiwanese single-payer National Health Insurance Administration identified the eligible patients for this study. A postal reminder letter regarding medication duplication was mailed to the patients in the study group, and no information was provided to the comparison group. Generalized estimation equation models with a difference-in-differences analysis were used to estimate the effects of the reminder letters.

Results: Each group included 11,000 patients. Those who had received the reminder letter were less likely to receive duplicated medications in the subsequent 2 quarters (postintervention 1: odds ratio [OR]=0.95, 95% CI=0.87-1.03; postintervention_2: OR=0.99, 95% CI=0.90-1.08) and had fewer days of duplicated medications (postintervention 1: β=-0.115, P =0.015; postintervention 2 (β=-0.091, P =0.089) than those who had not received the reminder letter, showing marginal but significant differences.

Conclusions: A one-off reminder letter nudge could mildly decrease the occurrence of duplicated medications. Multiple nudges or nudges incorporating behavioral science insights may be further considered to improve medication safety in health systems without gatekeeping.