Aim: The purpose of this study was to clarify the effects of self-management behavior, quality of life (QOL), biometric data, and medical costs on kidney transplant patients in a 1-year prospective cohort study.

Methods: The participants were 225 patients who underwent kidney transplantation. Self-management behavior was measured using the self-administered Kidney Transplant Self-management scale (Japanese version), and health-related QOL was examined using Medical Outcomes Study 12-Item Short-Form Health Survey. Participant characteristics and biometric data were obtained from the patients’ electronic medical record data, and medical costs were calculated from medical fee billing information (EF files).

Results: Among the 142 participants whose data were analyzed, the interaction of self-management behavior and time was identified as significant in Role/Social component summary QOL score (F(1, 50) = 14.85, p < .001)and Triglyceride (TG) value (F(1, 61) = 9.83, p < .001). Regarding medical expenses, the high self-management group had reduced outpatient medical expenses (F(1, 123) = 4.06, p = .044), but there was no significant difference in the total outpatient and total medical costs.

Conclusion: The results suggested that appropriate self-management behavior of kidney transplant patients had a positive effect on quality of life, biometric data.