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

Abstract

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. © 2007 The Authors.