METHODS
A cross-sectional assessment of the antihypertensive medicines utilization was conducted between 1st June and 31st June 2012 among 300 randomly selected hypertensive patients diagnosed and managed at the Medical Outpatient Clinic of the University College Hospital (UCH), Ibadan. This is a 900-bed premier Teaching Hospital with medical residents located in Ibadan, Southwestern Nigeria. It is affiliated with the University of Ibadan and serves as a major tertiary referral center in Nigeria. UCH has fifty-two service and clinical departments and runs seventy-five consultative outpatient clinics per week in forty-five specialties and sub-specialties. Ibadan, where the study site is located, is one of the largest cities in sub-Saharan Africa and consisted of 11 local government areas. It has an estimated population of
2.5 million consisting of varied backgrounds and ethnicities. Ethical clearance and approval of the study protocols was granted by the Joint University of Ibadan/University College Hospital Research and Ethics Committee. All the patients who presented at the Hypertension unit of the Medical Outpatient Clinics at the study site within the study period were included and constituted the sample frame. The average number of patients seen at the weekly Hypertension clinic was 90. Patient selection was done after clinic appointment cards had been collected and patients were seated in the waiting area. Seventy-five clinic appointment cards were randomly drawn weekly from the collected pool. The case notes of the selected seventy five patients were retrieved for data extraction after physicians’ consultation.
Data were extracted from the case notes of the randomly selected 300 patients using pre-tested data collection instruments. The first draft of the instrument was pre-tested with the case notes of ten patients at the study site to assess completeness and relevance of data capture. The final draft of the instrument was modified based on the results of pre-testing, but the data collected during pre-testing was not included in the final result. The data collected from patients’ case notes were:
- i) Patients’ hospital number, Age and Gender
- ii) Systolic and diastolic blood pressure readings at first clinic attendance.
- iii) Systolic and diastolic blood pressure readings at last clinic attendance
- iv) Hypertension diagnosis and co-existing diseases.
- v) Antihypertensive drugs prescribed with specific focus on ACEIs and ARBs.
- vi) Documentation of adverse drug reactions associated with ACEIs /ARBs.
- vii) Baseline and follow-up laboratory monitoring for serum potassium, urea and creatinine
- viii) Monthly cost of antihypertensive drugs and Monthly cost of ACE inhibitors and ARBs.
- ix) Potential Drug-drug interactions and contra-indications
The classification of hypertension diagnosis was based on the Seventh report of the Joint National Committee for the prevention, detection, evaluation and treatment of hypertension, and the average systolic / diastolic blood pressure reading recorded at the first clinic attendance were used for the hypertension diagnosis. The documented systolic and diastolic blood pressure levels at the last clinic attendance was adjudge as adequately controlled if they are less than 140/90 mmHg.23 The appropriateness of the antihypertensive drug doses, dosing interval and potentially harmful drug interactions were assessed using the British National Formulary (March, 2010).24 Data analysis was carried out with descriptive and chi-square statistics using Statistical Program for the Social Sciences (SPSS) version 15.0 with p<0.05 considered significant.