Abstract
Dietitian-led medical nutrition therapy (MNT) in patients with type 2 diabetes becomes less efficacious as the duration of diabetes increases, but increasing the frequency of MNT counseling might counteract this. In recent years, the transtheoretical model (TTM) has been adopted for nutrition therapy in patients with type 2 diabetes and emphasizes that approaches which raise the stage of behavior change and self-efficacy in patients are effective. Here, the influences of the duration of diabetes and frequency of nutrition therapy on stage of dietary behavior change and self-efficacy were surveyed. Also, the relationships of improvement in HbA1c levels with alterations in stage of dietary behavior change and self-efficacy score were analyzed. Data were collected before and 6 months after initiation of MNT from 619 patients with type 2 diabetes treated at 281 hospitals in Japan. At 6 months after initiation of MNT, both stage of dietary behavior change and self-efficacy score were higher for greater MNT counseling frequency and shorter duration of diabetes. Furthermore, the improvement in HbA1c levels following 6 months of MNT increased progressively with the stage of dietary behavior change and self-efficacy score. The results show that raising the stage of dietary behavior change and increasing self-efficacy were the major factors influencing HbA1c improvement. These findings were independent of sex, changes in medications, baseline HbA1c levels, duration of diabetes, and MNT counseling frequency. The MNT based on TTM effectively advanced the stages of dietary behavior change, increased self-efficacy, and alleviated diabetes. However, the duration of diabetes was found to influence the efficacy of the MNT.
