Improving medication adherence through calendar packaging: results of a randomized controlled trial among hypertensive patients

Abstract

Objective This study aimed to investigate the effect of calendar packaging (CP) on medication adherence among hypertensive patients in Malaysia. Setting Outpatient Pharmacy Department, Kulim Hospital. Methods This was a parallel randomized controlled trial of CP (intervention group) versus normal pack (control group) for patients who were on daily dose antihypertensive drug (amlodipine).The primary outcome was medication adherence to amlodipine, assessed by medication possession ratio (MPR), percentage of on-time refills and Malay Version Morisky medication adherence scales. Key findings Eighty-three patients participated. The mean age (standard deviation) was 55.85 (10.25) and 56.55 (10.42) for intervention and control group respectively. This study found that intervention group has better medication adherence score than the control group measured by MPR, Morisky medication adherence score (P < 0.05) and percentage of on-time refills (P < 0.01). Intervention group showed a significantly lower systolic and diastolic blood pressure (P < 0.05) compared to control group. Intervention group was significantly associated with higher medication adherence measured by MPR (β = 0.006, P < 0.05), Morisky scale (β = 0.365, P < 0.05) and percentage of on-time refill (β = 0.063, P < 0.01); in addition lower systolic blood pressure (β = −4.4, P < 0.05) after controlling for the study period and patient age. Conclusions This study found that CP could improve adherence to medication among hypertensive patients. The results also suggest possible improvement in blood pressure with the use of CP.