Assessing patient adherence to anti‐hypertensive drug therapy: can a structured pharmacist‐conducted interview separate the wheat from the chaff?

Objective To identify determinants of adherence and assess the impact of structured pharmacist‐conducted interviews in determining patients' adherence to prescribed anti‐hypertensive medications in a secondary care setting in Nigeria. Method The study was conducted in a secondary care facility located in Ibadan, Southwestern Nigeria. Two methodological approaches were employed. The first phase was pharmacist‐conducted, pre‐physician consultation, cross‐sectional interviews of 400 hypertensive patients who presented at the study site within the 2‐month study period. The second phase was a follow‐up review of case notes of these patients after they had left the physician's office. Key findings The outcome of the pharmacist‐conducted pre‐physician consultation interview shows that financial difficulty was the most frequently identified factor responsible for patients' non‐adherence to anti‐hypertensive drug therapy (64%). A drug holiday, varying from 5–14 days per month, was the coping strategy adopted by patients to circumvent this difficulty. Only 48% (192) of patients were aware of the negative consequences of non‐adherence with anti‐hypertensive drug therapy, and of these, 75% were adherent. The level of awareness was significantly higher in adherent patients ( P < 0.001). Sixty‐seven per cent (268) of patients use a daily medication reminder (DMR) to assist them in taking their anti‐hypertensive drugs, and of these 65.7% were adherent. The use of DMRs was significantly higher among adherent patients ( P < 0.01). A meal time was the most frequently used DMR (88%). Forty‐one per cent (164) of patients had additional measurement of their blood pressure at pharmacies (65.9%) and neighbourhood private hospital (34.1%), and of these 75.6% were judged to be adherent with their prescribed drug therapy. Additional measurement of blood pressure was significantly higher in adherent patients ( P < 0.001). Fifty‐one per cent of the cohort were judged by pharmacists as non‐adherent during pre‐consultation interviews (phase 1), while physicians judged 25% of the same cohort as non‐adherent during consultation (phase 2). The structured pharmacist‐conducted pre‐physician consultation interviews were significantly better at identifying patients who were non‐adherent with prescribed anti‐hypertensive drugs ( P < 0.01). Conclusion A brief structured pharmacist‐conducted interview can be a valuable tool in assessing and/or identifying determinants of adherence with anti‐hypertensive drug therapy.