Adherence to multiple drug therapies: refill adherence to concomitant use of diabetes and asthma/COPD medication

Abstract

Purpose: To investigate whether patients with drugs for two chronic diseases, type 2 diabetes and asthma/chronic obstructive pulmonary diseases (COPD), showed the same refill adherence pattern in relation to their drug treatments during a 3-year period.

Methods: Patients 50 years and older who had been dispensed diabetes and asthma/COPD drugs in the county of Jämtland during 2001-2003 were included. The refill adherence was calculated based either on prescribed dosage or defined daily dose (DDD). A patient profile graph for each patient was constructed including the date of each dispensation and the time period covered by the dispensed drugs. For each patient, the dispensation pattern and the treatment persistency over time were determined.

Results: In total, 56 patients were included in the study. Satisfactory refill adherence was found for 68% of the repeat prescriptions for diabetes drugs and for 42% of the repeat prescriptions for asthma/COPD drugs. About half (52%; 29/56) of the patients showed the same dispensation patterns for both diabetes and asthma/COPD drugs, and 86% (25/29) of these patients had a satisfactory refill adherence. However, there was no correlation or agreement regarding the dispensation patterns for diabetes and asthma/COPD drugs.

Conclusions: Patients showed higher refill adherence for their diabetes drugs than their asthma/COPD drugs. Our hypothesis that patients with satisfactory refill adherence to antihyperglycaemic drugs would also have satisfactory refill adherence to asthma/COPD drugs, was not supported.