Poor adherence to medication and salt restriction as a barrier to reaching blood pressure control in patients with hypertension: Cross-sectional study from 12 sub-Saharan countries.

BACKGROUND: Sub-Saharan Africa is experiencing a rising burden of hypertension. Antihypertensive medications and diet are the cornerstone of effective hypertension control. AIMS: To assess adherence to medication and salt restriction in 12 sub-Saharan countries, and to study the relationship between adherence and blood pressure control in patients with hypertension. METHODS: We conducted a cross-sectional survey in urban clinics in twelve sub-Saharan countries. Data were collected on demographics, treatment and adequacy of blood pressure control in patients with hypertension attending the clinics. Adherence was assessed by questionnaires completed by the patients. Hypertension grades were defined according to European Society of Cardiology guidelines. Association between adherence and blood pressure control was investigated using multilevel logistic regression analysis, adjusting for age, sex and country. RESULTS: Among the 2198 patients, 77.4% had uncontrolled blood pressure, 34.0% were poorly adherent to salt restriction, 64.4% were poorly adherent to medication and 24.6% were poorly adherent to both. Poor adherence to salt restriction (odds ratio [OR] 1.33, 95% confidence interval [CI] 1.03-1.72), medication (OR 1.56, 95% CI 1.25-1.93) or both (OR 1.91 1.39-2.66) was related to uncontrolled blood pressure. Moreover, poor adherence to both medication and salt restriction was related to a 1.52-fold (95% CI 1.04-2.22), 1.8-fold (95% CI 1.22-2.65) and 3.08-fold (95% CI 2.02-4.69) increased likelihood of hypertension grade 1, 2 and 3, respectively. CONCLUSIONS: High levels of poor adherence to salt restriction and medication were noted in this urban sub-Saharan study; both were significantly associated with uncontrolled blood pressure, representing major opportunities for intervention to improve hypertension control in sub-Saharan Africa.

Factors associated with poor adherence to medication among hypertensive patients in twelve low and middle income Sub-Saharan countries.

INTRODUCTION: Over the past few decades, the prevalence of hypertension has dramatically increased in Sub-Saharan Africa. Poor adherence has been identified as a major cause of failure to control hypertension. Scarce data are available in Africa. AIMS: We assessed adherence to medication and identified socioeconomics, clinical and treatment factors associated with low adherence among hypertensive patients in 12 sub-Saharan African countries. METHOD: We conducted a cross-sectional survey in urban clinics of both low and middle income countries. Data were collected by physicians on demographics, treatment and clinical data among hypertensive patients attending the clinics. Adherence was assessed by questionnaires completed by the patients. Factors associated with low adherence were investigated using logistic regression with a random effect on countries. RESULTS: There were 2198 individuals from 12 countries enrolled in the study. Overall, 678 (30.8%), 738 (33.6%), 782 (35.6%) participants had respectively low, medium and high adherence to antihypertensive medication. Multivariate analysis showed that the use of traditional medicine (OR: 2.28, 95%CI [1.79-2.90]) and individual wealth index (low vs. high wealth: OR: 1.86, 95%CI [1.35-2.56] and middle vs. high wealth: OR: 1.42, 95%CI [1.11-1.81]) were significantly and independently associated with poor adherence to medication. In stratified analysis, these differences in adherence to medication according to individual wealth index were observed in low-income countries (p<0.001) but not in middle-income countries (p = 0.17). In addition, 26.5% of the patients admitted having stopped their treatment due to financial reasons and this proportion was 4 fold higher in the lowest than highest wealth group (47.8% vs 11.4%) (p<0.001). CONCLUSION: This study revealed the high frequency of poor adherence in African patients and the associated factors. These findings should be useful for tailoring future programs to tackle hypertension in low income countries that are better adapted to patients, with a potential associated enhancement of their effectiveness.

Socioeconomic Status and Hypertension Control in Sub-Saharan Africa: The Multination EIGHT Study (Evaluation of Hypertension in Sub-Saharan Africa).

Systemic hypertension is a rapidly growing epidemic in Africa. The role of socioeconomic status on blood pressure control has not been well studied in this part of the world. We, therefore, aimed to quantify the association of socioeconomic status both at the individual and at the country level with blood pressure control in Sub-Saharan Africa. We conducted a cross-sectional survey in urban clinics of 12 countries, both low income and middle income, in Sub-Saharan Africa. Standardized blood pressure measures were made among the hypertensive patients attending the clinics. Blood pressure control was defined as blood pressure <140/90 mm Hg, and hypertension grades were defined according to the European Society of Cardiology guidelines. A total of 2198 hypertensive patients (58.4±11.8 years; 39.9% men) were included. Uncontrolled hypertension was present in 1692 patients (77.4%), including 1044 (47.7%) with ≥grade 2 hypertension. The proportion of uncontrolled hypertension progressively increased with decreasing level of patient individual wealth, respectively, 72.8%, 79.3%, and 81.8% (P for trend, <0.01). Stratified analysis shows that these differences of uncontrolled hypertension according to individual wealth index were observed in low-income countries (P for trend, 0.03) and not in middle-income countries (P for trend, 0.26). In low-income countries, the odds of uncontrolled hypertension increased 1.37-fold (odds ratio, 1.37 [0.99-1.90]) and 1.88-fold (odds ratio, 1.88 [1.10-3.21]) in patients with middle and low individual wealth as compared with high individual wealth. Similarly, the grade of hypertension increased progressively with decreasing level of individual patient wealth (P for trend, <0.01). Strategies for hypertension control in Sub-Saharan Africa should especially focus on people in the lowest individual wealth groups who also reside in low-income countries.