[Epidemiological characteristics and clinical features of black African subject's resistant hypertension]

Abstract

Introduction: Few studies in sub-Saharan Africa were interested in resistant hypertension. The objectives of this study were to determine the frequency of resistant hypertension in hypertensive black African population, and to describe its clinical and therapeutic features.

Patients and methods: From May 1, 2010 to May 31, 2012, we included consecutively hypertensive followed in two hospitals in the city of Ouagadougou, under antihypertensive treatment at optimum dose and observant. Patients whose blood pressure was uncontrolled despite a triple antihypertensive therapy at the optimal dose including a diuretic associated with dietary measures have received ambulatory blood pressure monitoring. Following this examination, patients whose blood pressure was ≥135/85mmHg during the day and/or ≥120/70mmHg at night were considered resistant hypertension. We investigated the cardiovascular risk factors as well as target organ damages. We combined spironolactone 50mg in treatment when absence of contra-indication appreciated the evolution of blood pressure under this treatment. The measurement of plasma renin activity was not performed. Statistical analysis was performed using SPSS Version 17 for Windows.

Results: We included 692 patients with 14.6% of resistant hypertension. The average age of patients was 54.8±11.1years in the general population, 56.5±11.8years in the subgroup of non-resistant hypertension and 64.2±5.4years in the subgroup of resistant hypertension. The symptoms were represented by headache (11.9%), dizziness (9.9%) and chest pain (8.9%). Modifiable cardiovascular risk factors were dominated by dyslipidemia, diabetes and obesity/overweight. These risk factors were significantly more frequent in the subgroup of resistant hypertension. The global cardiovascular risk was high in 24.9% of cases in the general population, 22.5% in the subgroup of non-resistant hypertension and 38.6% in the subgroup of resistant hypertension. The target organ damages were significantly more frequent in the same subgroup of resistant hypertension. After addition of spironolactone, 21.8% of resistant hypertensive patients were controlled.

Conclusion: This study shows that resistant hypertension is common in black Africans. It is mostly subjects of the sixth decade, with limited economic income and living in rural areas. In the absence of contra-indication, spironolactone contributed to decrease the morbidity of this pathology.

Keywords: Afrique Noire; Black Africa; Burkina Faso; HTA résistante; Resistant hypertension.