Several studies have been conducted to understand adherence and to identify the determinants associated with it showing that medication adherence is influenced by numerous factors that may be related to patients and medication. There are no data of large-scale medication adherence originating in Japan. In this study, we examined non-adherence and predictive factors of T2DM patients in Japan. This was a retrospective cohort study using a Japanese claims database of patients with type 2 diabetes. Adherence to therapy was measured using the proportion of days covered (PDC) method over a fixed period of 3 years. If PDC <80%, patients were considered non-adherent, a commonly used standard. To assess the odds ratio (OR) of non-adherence, we performed a logistic regression analysis, having adjusted for patient characteristics. The final sample contained 885 patients. The mean PDC was 79.6%, with 50.2% of patients classified as non-adherence. The mean number of medicines was 2.4, with 11.1% of patients classified as polypharmacy. According to the inflection point of the ROC curve, the cut-off value of the number of outpatient visits associated with adherence was 17 times. In the multivariate logistic regression analysis, polypharmacy (OR:0.18), the older age (60y∼ OR:0.37, 50y∼OR:0.39) showed lower odds ratio. Men (OR:2.20), 17 or less times of outpatient visits in 3 years (OR:27.1) showed higher odds ratio. In this study, we investigated medication non-adherence in 3 years and showed adherence adequacy a little lower to that reported previously, which is one year observation period. Also, medication adherence tended to be lower in younger ages and cases with fewer drugs. Maintaining good medication adherence and achieving the targeted HbA1c in these cases are important for suppressing the onset of diabetic complications. We think that it is necessary to consider methods of intervention aimed at maintaining good medication adherence, such as by utilizing on-line medical treatment.


T. Horii: None. K. Momo: None. T. Yasu: None. Y. Kabeya: None. K. Atsuda: None.


Japan Association for Diabetes Education and Care

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