Prevalence and factors associated with antihypertensive drug therapy problems among hypertensive patients, southwestern Uganda: a multicenter cross-sectional study

Abstract Worldwide, half of the patients with hypertension have uncontrolled blood pressure (BP) even in presence of effective medical therapy and this is mostly due to drug therapy problems (DTPs). Therefore, this study was aimed to determining the prevalence and the factors associated with these DTPs among hypertensive patients. A hospital-based, prospective, cross-sectional study was conducted among 159 patients from Kampala International University and Ishaka Adventist Hospitals. Participants were interviewed using a structured questionnaire to obtain data on socio-demographics, history of drug allergies, lab data, current medication, and medication adherence. The identification and classification of DTPs were based on the pharmaceutical care practice model. The Hill-Bone Medication Adherence Scale was used to assess patients’ medication adherence. The appropriateness, effectiveness and safety of drug therapy was evaluated using Uganda Treatment Guideline. Descriptive analysis was used to determine prevalence of DTPs and logistic regression was used to determine association between the independent and dependent variable. Variables were considered statistically significant at p value < 0.005. A number of 116 DTPs were identified among 159 participants. The overall prevalence of DTPs from the two hospitals was 56.6%, indicating that over half of the patients experience at least one DTP. “Dosage too low” was the most common DTP (36.2%), followed by ADRs (17.2%) and need for additional drug therapy (16.4%%), highlighting issues with suboptimal dosing and treatment. Study participants with uncontrolled BP were 2.47 times (adjusted odds ratio [AOR]: 2.47; 95% CI: 1.25–4.89; p-value = 0.009) more likely to experience DTPs compared to those with controlled BP. The findings revealed that over a half of the participants had antihypertensive related DTPs. The most common DTP was dosage too low indicating a need for dosage management. Patients with uncontrolled BP were more likely to experience antihypertensive related DTPs compared to those with controlled BP.