Assessment of medication adherence and the costs associated with a calendar blister pack intervention among hypertensive patients in Malaysia: A randomized controlled trial

OBJECTIVES: To assess the efficacy and costs of a calendar blister packaging intervention used to improve medication adherence. METHOD: A parallel randomized controlled trial was conducted with 73 hypertensive patients (intervention group = 35, control group = 38) at Hospital Kulim, Malaysia, for 7 months. RESULTS: The intervention group demonstrated a significant improvement in medication possession ratio (p < 0.05) and percentage of on-time refills (p < 0.01) compared to control group. In addition, there was significantly lower blood pressure (p < 0.05) in intervention group. From the provider perspective, the average annual treatment cost per patient in the intervention group was MYR 2178.66 (~USD 526.95) (95% confidence interval = 1786.39–2570.94) compared to MYR 2693.09 (~USD 651.37) (95% confidence interval = 1903.23–3482.95) in the control group. CONCLUSION: This study provides evidence that calendar blister packaging has a positive impact on medication adherence, blood pressure and also has the potential for considerable cost savings.