Antihypertensive Medications Adherence Among Nigerian Hypertensive Subjects in a Specialist Clinic Compared to a General Outpatient Clinic

Abstract

Background: Poor adherence to antihypertensive medications has been linked with increased cardiovascular risk and mortality in many population. Africans have been shown to have a worse prognosis from hypertension, poorer blood pressure control, and increased risk of complications arising from hypertension compared to Caucasians.

Aim: The aim was to describe the level of adherence to antihypertensive medications, its determinants and whether any difference exist between those attending specialty clinic or general outpatient department (GOPD) Clinic in a Nigerian University Teaching Hospital.

Subjects and Methods: An analytical cross.sectional study. The Morisky scale was used to assess for adherence to antihypertensive medications. Clinical and demographic data were taken. Statistical analysis was performed using SPSS 17.0. (Chicago, IL, USA). P < 0.05 was taken as statistically significant.

Results: A total of 114 hypertensive subjects were recruited for this study. Seventy.nine were from the cardiology clinic whereas 35 were from the GOPD. They consisted of 60 males (52.6%, 60/114) and 54 females (47.4%, 54/110). The mean age was 63.6 (14.1) years. High adherence, low adherence and medium adherence as defined by Morisky scale was found in 36.8% (42/114), 23.9% (27/114) and 39.5% (45/114),  respectively. Adherence level was higher among those attending specialty clinic despite shorter duration of hypertension and use of more  medications. More than four.fifth of those attending cardiology clinic had at least medium level of adherence compared to a little bit over half of those attending GOPD clinic. Those with good adherence were likely to be older, had a higher level of education and higher average monthly income than those with poor adherence.

Conclusion: Poor adherence to medications is very common in the hypertensive Nigerians. Hypertensive subjects attending specialty clinic seems to have a better adherence to antihypertensive medications possibly due to the level of health education and information provided to patients. Effective health education and regular screening for compliance and adherence is a potential way to reduce cardiovascular risk associated with uncontrolled hypertension.

Keywords: Antihypertensive drugs, Determinants, General outpatient department clinic, Medication adherence, Nigeria, Specialist clinic