A study to investigate factors associated with poor adherence to antihypertensive population, at the University Teaching Hospital Lusaka, Zambia

Abstract

To determine the prevalence of drug adherence and factors associated with poor adherence to antihypertensive treatment Objective:among adults seen in the department of medicine at UTH. To investigate patient related and health care system related factors associated with poor adherence to antihypertensive Drugs.Methods:Adult patients aged 18 and above with previous diagnosis of essential hypertension receiving outpatient care in the UTH medical clinics were recruited from the first week of November to the second week of December 2010. Data was collected from patients regarding patients‘ social demographic factors, level of education, income per month and family history of hypertension. Information was also collected regarding health care system related factors and care giver related factors to patient non adherence using self report and modified hill bone compliance scale.Data was collected from 234 participants. The mean age was 57.8 ± 12.0 SD. 51 patients (22%) had diabetes mellitus and 44 patients (19%) had the diagnosis of heart failure. The commonest side effects of drugs reported in the study were dizziness and excessive urination, affecting 35% and 31% of patients, respectively. Patients on three antihypertensive drugs were less likely to be non-adherent (odds ratio 0.21, 95% CI 0.06-0.79) than patients taking only one drug.Majority (60%) of the patients were reviewed at least twice in the last 6 months at the time of the interview. 195 (83%) patients reported that drugs prescribed were not available at the hospital pharmacy, but 186 (79%) of these were able to purchase the drugs elsewhere.221 patients (94%) were counseled by the doctor on how to take medicines. Patients counseled by the nurse were more likely to be adherent than those not counseled by the nurse, OR 2.7 (1.0-7.3). Those who were counseled for more than 5 minutes had significantly less non-adherence as reported by both self report and modified Hill Bone with OR of 0.3(95% CI 0.2-0.8) and 0.3(95% CI0.1-0.5), respectively.In multivariable analysis, participants were more likely to be non-adherent by self-report if they had attained a primary level of education, had missed appointments due to lack of transport, or had experienced the side effect of dizziness. Patients with heart failure were more likely to be non-adherent based on the modified Hill-Bone scale, whereas those taking 3 antihypertensive drugs and those who were counseled for more than 5 minutes on drugs were significantly less likely to be non-adherent.Conclusion:The prevalence of adherence among hypertensive patients was found to be higher than anticipated. The factors associated with non-adherence included side effect of dizziness, missed appointment due to lack of transport, and living at a distance of more than 10 km from the hospital. Taking 3 BP drugs and receiving more than 5 minutes of counseling about how to take medications were both associated with decreased likelihood of non-adherence. This information provides baseline data to help improve and address the issues of adherence in hypertensive patients seen in our health institutions