High blood pressure (HBP), according to the WHO, is defined as systolic blood pressure greater than or equal to 140 mm Hg and/or diastolic blood pressure greater than or equal to 90 mm Hg, measured twice, on different days [1] confirmed by self-measurement or ambulatory blood pressure measurement (ABPM).

It constitutes a major public health problem and is considered to be the leading chronic disease in the world [2] . In March 2023, a report from the World Health Organization (WHO) estimated that, despite a stable global prevalence, the absolute number of people aged 30 to 79 years suffering from hypertension has doubled, from 648 million in 1990 to 1.28 billion people in 2019 [1] . This is strongly linked to the increase in life expectancy and the increased exposure to risk of the population such as the increase in the number of obese or overweight subjects [3] .

If the observed trends are confirmed by 2025, hypertension is expected to affect more than 1.5 billion people worldwide [4] .

Developing countries will be the hardest hit by the burden of hypertension, which will be added to that of communicable diseases. The data available to us on the African continent are alarming since they indicate prevalence rates comparable, particularly in cities, to those observed in Western societies [5] .

Furthermore, little data is currently available on the knowledge, treatment and control of HBP in sub-Saharan Africa. However, those that have been published are worrying. While the prevalence of hypertension is comparable in sub-Saharan African cities and in Western cities, this is not the case for the rates of screening, treatment and control of the disease. All studies indicate that less than half of hypertensive people are aware of this health problem and that very few of them follow a treatment. Less than 10% of hypertensive patients in sub-Saharan Africa are controlled [5] .

The objective of this work was to identify the factors associated with poor blood pressure control in hypertensive patients followed in the cardiology department of the Dalal Jamm National Hospital.

This was a retrospective, descriptive and analytical single-center study that took place from January 1, 2021 to December 31, 2021. It involved 109 files of hypertensive patients followed in the cardiology department of the Dalal Jamm National Hospital Center.

Patients were recruited after studying their files and agreeing to answer the questionnaire by telephone after free and informed consent in order to complete the data.

The inclusion criteria were as follows: any patient aged 18 years and over, known carrier of essential hypertension, followed in the department and treated for at least 03 months. We did not include patients who did not consent, were unreachable or unable to answer the questions due to cognitive or psychiatric disorders.

For each patient we assessed the socio-demographic data including the socio-economic level for which we used an estimation method involving different observable elements:

This assessment allowed us to classify the patients into 3 socio-economic levels:

We also collected cardiovascular risk factors (diabetes, dyslipidemia, obesity), lifestyle (smoking, regular physical activity: at least 30 to 45 min, 3 to 4 times a week by cycling, walking, running, swimming, etc.), clinical and paraclinical data. The data collected on hypertension were the duration of progression, quality of follow-up, treatment and therapeutic compliance by applying the GIRERD [6] . This test is used to assess the level of compliance, i.e. whether the treatment is taken regularly and as prescribed or during a consultation with a healthcare professional. The patient will have to answer “yes” or “no” to each question.

Questions:

Test interpretation:

Total yes = 0 Total yes = 1 or 2 Total yes ≥ 3

Score = 0: Good compliance

Score = 1 or 2: Minimal compliance problem

Score ≥ 3: Poor compliance

Blood pressure control was defined as blood pressure below 140/90 mm Hg.

The data collected were entered into Excel 2010 on a previously established form. The analysis was performed with RStudio 4.6 software. An in-depth approach was devoted to examining the relationships between variables using the Chi-square independence test. We analyzed the p-values to obtain significant perspectives on the potential links between the parameters studied. The significance level of the test was 5%. We had incorporated a logistic regression method to deepen our understanding of the relationships between the variables. The significance level of the test was 5%, but it also depended on the coefficient (Estimate).

Among the 109 patients who participated in the study; there were 74 women and 35 men. The mean age was 61.9 ± 12.14 years and the most representative age group was 60 - 70 years. The majority of patients (51.4%) were educated. Sedentary lifestyle (76.1%; n = 83) was the most common cardiovascular risk factor and 43 patients (39.4%) had dyslipidemia. The mean duration of hypertension was 6.62 ± 4.62 years. It was at least 2 years in 85.3% of hypertensive patients. Irregular follow-up was noted in 21.1% (i.e. 23 patients). All patients were on antihypertensive treatment: 33% on monotherapy, 42.2% on dual therapy and 19.2% on triple therapy. The assessment of therapeutic compliance showed 30.3% of patients compliant, 31.2% non-compliant and 38.5% minimal compliance problems. The mean blood pressure was 162.4 ± 21/96.16 ± 13.6 mm Hg. Blood pressure was not controlled in 51 patients or 46.8% of patients.

The bivariate analysis found the following factors associated with poor blood pressure control: sedentary lifestyle (p < 0.0001), irregular monitoring (p = 0.0008), therapeutic non-compliance (p < 0.0001), taking oral herbal medicine (p = 0.040) and low socio-economic level (p = 0.007) ( Table 1 ). Multivariate analysis revealed that therapeutic non-compliance was a factor associated with the lack of blood pressure control ( Table 2 ).

HBP: High Blood Pressure; CVRF: Cardiovascular Risk Factor.

The level of poor blood pressure control in this study was 46.8%. This rate could be explained by the absence of ambulatory blood pressure measurement in patients in order to eliminate a “white coat” effect. Furthermore, it is close to the data in the literature on the African environment and remains insufficient [7] - [9] .

In the poor control of blood pressure in hypertensive patients in sub-Saharan Africa, several studies have incriminated therapeutic inertia, high stress levels, side effects of antihypertensive, anxiety, advanced age, self-medication and duration of the disease greater than or equal to five years [7] [10] [11] . In this study, the factor associated with poor blood pressure control was therapeutic non-compliance.

Treatment compliance is a crucial factor for blood pressure control. Several factors considered as determinants of therapeutic non-compliance have been studied in Africa. The most important factors incriminated are the level of knowledge about the disease and those related to the treatment: side effects, number of drugs in addition to antihypertensive treatment [12] . The appropriation of the treatment by the patient is an important element on which prescribers should insist, hence the fundamental place of the diagnosis of announcement and therapeutic education. This is integrated into the framework of a global response to achieve a comfortable blood pressure control rate as achieved by some low- to middle-income countries.

This work revealed that therapeutic nonobservance was the factor associated with poor blood pressure control. It would be essential to identify the factors associated with this nonobservance, to promote therapeutic education for patients and to make care accessible.

We were faced with the absence of certain biological tests, self-measurement and ABPM in several patients, which did not allow us to better assess the cardiovascular risk and the level of control.