Pill Counting in the Determination of Factors Affecting Medication Adherence in Patients with Type 2 Diabetes: A Retrospective Observational Study

INTRODUCTION

For medication adherence, pill counting has higher accuracy in objective assessment. However, previous reports have shown that factors such as psychological bias and other people's involvement in managing and helping patients take their medications may influence the outcomes. In Japan, all prescription medicines of patients are checked by medical reconciliation, and a pill count is performed during hospitalization. This study investigated factors affecting the medication adherence of patients with type 2 diabetes mellitus (T2DM), including patient- and medication-related factors, by pill counting using medical reconciliation in a situation where the patient's psychological bias is low.

METHODS

This study included 103 patients with T2DM who had been treated with oral hypoglycemic agents (OHAs) for at least 24 weeks. Patients whose OHAs were managed by another person were excluded. We calculated medication adherence values (MAVs) according to the following formula: MAV = (total prescription days - prescription days of OHAs brought when admitted)/(days from the start of OHAs to hospitalization). The relationship between MAVs and patient- and medication-related factors was analyzed.

RESULTS

On multiple linear regression analysis of patient-related factors with P < 0.10 in the univariate analysis as explanatory variables, a lower number of chronic diseases (β = 0.017; P < 0.001) and higher number of OHAs (β = - 0.021; P = 0.04) were independent factors for lower MAV. Medication-related factors were not found to be independent factors.

CONCLUSIONS

Our findings suggest that poor adherence was independently associated with lower number of chronic diseases and higher number of OHAs in patients with T2DM.