Secondary Hypertension in Sub-Saharan African Populations: A Retrospective Study between 2011 and 2016 at Regional Hospital of Saint-Louis, Senegal

Abstract

Introduction : High blood pressure (HBP) is a worldwide health issue responsible of high cardiovascular morbidity and mortality. Even though essential HBP is far the most frequently reported in patients, secondary causes must be known because of their severity and the possibility of aetiological treatment. No recent epidemiological data are available about secondary causes of HBP in black African populations. The aim of this study was to describe aetiological patterns of secondary HBP in patients followed at Saint-Louis Hospital. Patients and Method : We conducted a retrospective and descriptive study in regional hospital of Saint-Louis. All patients aged ≥15 years old admitted from January 1st 2011 to January 31st 2015 in internal medicine, nephrology, emergency and cardiology departments were included. Clinical, paraclinical data and patients outcomes were collected from medical records. Hypertension was defined according to JNC8 criteria. Secondary HBP was considered if explorations identified a clear aetiology to hypertension. Statistical analysis was done with Excel 2010 and STATA 12.0. Results : We included 9253 patients with mean age of 35 ± 12 years (15 - 83 years) and sex-ratio of 1.6. Overall 67.5% of patients had hypertension and secondary causes were found in 10.5% of them. The majority of patients presented clinical symptoms suggesting a secondary cause of HBP and first-line laboratory explorations were normal in half of cases. Renal diseases were responsible for 79.1% of secondary HBP cases mainly dominated by glomerulonephritis (22.6%), vascular nephropathies (18.7%) and autosomal dominant polycystic kidney disease (5.8%). They were followed by preeclampsia (13.6%) and endocrinal aetiologies such as hyperthyroidism (5.8%), hypercorticism (0.5%), pheochromcytoma (0.5%), primary hyperparathyroidism (0.4%) and Conn’s adenoma (0.1%). Combination of ≥3 antihypertensive drugs was necessary in 71.5% of cases and surgical treatment was performed in three patients. Blood pressure was normalized in only 27.7% of patients. Conclusion : Secondary causes are frequent in our young patients with HBP. In the majority of patients complete clinical examination and minimal laboratory investigations recommended by World Health Organisation can give an aetiological orientation that needs further radiological and hormonal explorations.