Antihypertensive prescription among black patients without compelling indications: prescription, effectiveness, quality and cost of medication

BACKGROUND: Hypertension remains one of the leading causes of death in Nigeria. Appropriate and cost-effective treatment of the disease is necessary to reduce mortality. This study evaluates (i) the prescription patterns and quality (ii) blood pressure control and (iii) cost of medication among patients with hypertension uncomplicated by co-morbid diseases or compelling indications. METHOD: Patients with uncomplicated hypertension attending three clinics in the University College Hospital, Ibadan in Nigeria were recruited into this study. Information on demographics, antihypertensive medication prescribed, blood pressure measurements, and cost of medications were collected for each patient. Antihypertensive medications were classified according to the Anatomical Therapeutic Chemical (ATC) classification system and the Defined Daily Dose (DDD) system. The frequency of usage of each drug class and their prescribed doses per patient/day were calculated and compared with the DDD to assess the quality of prescription. Cost of antihypertensive medication was calculated for each patient and reported as cost per patient/day and cost per patient/month. Effect of variables on BP control was ascertained. Statistical analyses were done using SPSS, chi-square and correlation test was used to test for associations. RESULT: A total number of 1050 hypertensive patients were included in this study. The mean age was 60 years, females made up 62% of the study population. A high level of polypharmacy (87%) and sub-optimal blood pressure control was observed. An increase in blood pressure was observed with increase in the number of medication prescribed (χ(2) = 33.618, p < 0.001; r = .18, p < 0.001). The most prescribed antihypertensive medication either as a single therapy or a fixed-dose combination was diuretic. About 54% of the prescribed daily doses of antihypertensive medication exceeded the DDD. The total monthly expenditure on antihypertensive drugs was approximately N3.2 million ($15,300). CONCLUSION: Study findings show a high level of polypharmacy and non-generic prescribing. Increased prescribing of drugs that are cost-effective, as well as prescription of fixed dose combinations (FDCs), is recommended in hypertensive patients. This is necessary to control blood pressure while increasing treatment adherence.