Utilization Study of Antihypertensive Medicines Among Insured Patients at a Public Tertiary Healthcare Facility in Nigeria

Background: Access to essential medicines through health insurance contributes substantially towards achieving hypertension control in hypertensive sub-population of a nation. Objectives: This study aimed to estimate the gender-based antihypertensive medicines use, to describe utilization patterns, and to estimate prescribing adherence to the health insurance guideline. Methods: A descriptive, cross-sectional, retrospective review of paper-based prescriptions with at least an antihypertensive medicine written for insured outpatients from 1st January – 31st December 2013 at a Nigerian Federal Teaching Hospital was conducted. The prescription volume and Anatomic Therapeutic Chemical/Defined Daily Dose (DDD) methodology was used to estimate the extent of utilization of antihypertensive medicines among the study population. Drug utilization ninety percent (DU90%) was used to quantify the index of adherence to the National Health Insurance Scheme (NHIS) guideline. Differences in proportions were investigated with Pearson chi-square test (χ2). A p-value of less than 0.05 was considered statistically significant. Results: Females recorded significantly higher antihypertensive medicines use compared to their male counterparts (61.5% versus 38.5%, p < 0.05). Diuretics (32.1% and 9935.28 DDD) and calcium channel blockers (32.1% and 8286 DDD) were the most commonly prescribed and utilized antihypertensive medicine classes. The index of adherence to the NHIS standard treatment guideline is 80.7%. Conclusion: This study showed that diuretics (most frequently hydrochlorothiazide) and calcium channel blockers (most frequently amlodipine) were the most utilized antihypertensive medicine classes. Physicians’ prescribing patterns fell below the hundred percent benchmark of the country’s National Health Insurance programme guideline with respect to antihypertensive medicines.