BACKGROUND: Patients with chronic conditions, including kidney transplanted recipients, are required to actively participate in their continuous care and maintain motivation to adhere consistently to treatment. OBJECTIVES: Our study aimed to test long-term effectiveness of a new health communication intervention designed to improve on medication adherence and health literacy in kidney transplant recipients 2 years following transplantation. DESIGN: A randomised controlled non-blinded study was conducted between March 2020 and August 2023. PARTICIPANTS: One hundred and ninety-five kidney transplant recipients were included. MEASUREMENTS: Primary outcomes were self-reported medication adherence, measured by the BAASIS questionnaire, and health literacy, measured by the Health Literacy Questionnaire. The response rate was 87% (170 of 195 patients). RESULTS: This study showed a significant difference between groups in favour of the intervention group for medication adherence (p <
0.02) and two essential Health Literacy Questionnaire domains-'navigating the health care system' (p <
0.02) and 'having social support for health' (p >
0.03)-2 years after transplantation. Regarding health literacy, three Health Literacy Questionnaire domains showed a significant correlation with adherence: 'having sufficient information to manage health' (p <
0.04), 'having social support for health' (p <
0.04), and 'ability to understand health information well enough to know what to do' (p <
0.05). CONCLUSION: The findings in the study highlight the pivotal role of health communication in enhancing medication adherence and supporting important health literacy aspects for kidney transplant recipients.