Samuel Kingue

The prevalence of hypertension in seven populations of west African origin.

OBJECTIVES This study was undertaken to describe the distribution of blood pressures, hypertension prevalence, and associated risk factors among seven populations of West African origin. METHODS The rates of hypertension in West Africa (Nigeria and Cameroon), the Caribbean (Jamaica, St. Lucia, Barbados), and the United States (metropolitan Chicago, Illinois) were compared on the basis of a highly standardized collaborative protocol. After researchers were given central training in survey methods, population-based samples of 800 to 2500 adults over the age of 25 were examined in seven sites, yielding a total sample of 10014. RESULTS A consistent gradient of hypertension prevalence was observed, rising from 16% in West Africa to 26% in the Caribbean and 33% in the United States. Mean blood pressures were similar among persons aged 25 to 34, while the increase in hypertension prevalence with age was twice as steep in the United States as in Africa. Environmental factors, most notably obesity and the intake of sodium and potassium, varied consistently with disease prevalence across regions. CONCLUSION The findings demonstrate the determining role of social conditions in the evolution of hypertension risk in these populations.

Standardization of blood pressure measurement in an international comparative study

In the context of a collaborative study on the epidemiology of hypertension in populations of West African origin procedures for standardization of the measurement of blood pressure were evaluated. Comparisons of mean levels of blood pressure, which in large part determine prevalence rates, are highly sensitive to differences in technique. While rotating a single field team may be the ideal approach to multisite studies, it is not practical in international collaborative research. Appropriate techniques to standardize multiple teams over a long period of time have not been well developed, however. In the present study 8981 individuals were examined in eight sites in six countries with the standard mercury sphygmomanometer. An evaluation of the effectiveness of central training, site visits, monitoring of digit preference, and the use of an electronic device for internal standardization is described. In all but one of the sites reliability was high and comparable to the observers at the Coordinating Center. Digit preference for the entire set of measurements was limited (frequency of terminal zero = 23.5% for systolic and 28.9% for diastolic readings) and could be shown to have virtually no effect on prevalence rates or correlation estimates. Mean differences among observers within a given site and between sites were small (+/- 0-5 mmHg). While logistically complex, these methods can provide the basis for standardization in international comparative blood pressure surveys.

Prevalence, awareness, treatment and control of hypertension in a self-selected sub-Saharan African urban population: a cross-sectional study

Objectives Hypertension has been established as a major public health problem in Africa, but its specific contributions to disease burden are still incompletely understood. We report the prevalence and determinants of hypertension, detection, treatment and control rates among adults in major cities in Cameroon. Design Cross-sectional study. Settings Community-based multicentre study in major cities in Cameroon. Participants Participants were self-selected urban dwellers from the Center, Littoral, North-West and West Regions, who attended on 17 May 2011 a screening campaign advertised through mass media. Primary and secondary outcomes measures Hypertension defined as systolic (and/or diastolic) blood pressure (BP)≥ 140 (90) mm Hg, or ongoing BP-lowering medications. Results In all, 2120 participants (1003 women) were included. Among them, 1007 (prevalence rate 47.5%) had hypertension, including 319 (awareness rate 31.7%) who were aware of their status. The prevalence of hypertension increased with age overall and by sex and region. Among aware hypertensive participants, 191 (treatment rate 59.9%) were on regular BP-lowering medication, and among those treated, 47 (controlled rate 24.6%) were at target BP levels (ie, systolic (and diastolic) BP<140 (90) mm Hg). In multivariable logistic regression analysis, male gender, advanced age, parental history of hypertension, diabetes mellitus, elevated waist and elevated body mass index (BMI) were the significant predictors of hypertension. Likewise, male gender, high BMI and physical inactivity were associated with poor control. Conclusions High prevalence of hypertension with low awareness, treatment and control were found in this urban population; these findings are significant and alarming with consideration to the various improvements in the access to healthcare and the continuing efforts to educate communities over the last few decades.

Access to Diagnostic Tests and Essential Medicines for Cardiovascular Diseases and Diabetes Care: Cost, Availability and Affordability in the West Region of Cameroon

Objective To assess the availability and affordability of medicines and routine tests for cardiovascular disease (CVD) and diabetes in the West region of Cameroon, a low-income setting. Methods A survey was conducted on the availability and cost of twelve routine tests and twenty medicines for CVD and diabetes in eight health districts (four urban and four rural) covering over 60% of the population of the region (1.8 million). We analyzed the percentage of tests and medicines available, the median price against the international reference price (median price ratio) for the medicines, and affordability in terms of the number of days’ wages it would cost the lowest-paid unskilled government worker for initial investigation tests and procurement for one month of treatment. Results The availability of tests varied between 10% for the ECG to 100% for the fasting blood sugar. The average cost for the initial investigation using the minimum tests cost 29.76 days’ wages. The availability of medicines varied from 36.4% to 59.1% in urban and from 9.1% to 50% in rural settings. Only metformin and benzathine-benzylpenicilline had a median price ratio of ≤1.5, with statins being largely unaffordable (at least 30.51 days’ wages). One month of combination treatment for coronary heart disease costs at least 40.87 days’ wages. Conclusion The investigation and management of patients with medium-to-high cardiovascular risk remains largely unavailable and unaffordable in this setting. An effective non-communicable disease program should lay emphasis on primary prevention, and improve affordable access to essential medicines in public outlets.

Prevalence and Risk Factors of Hypertension in Urban Areas of Cameroon: A Nationwide Population-Based Cross-Sectional Study.

Accurate estimates of the prevalence rate of hypertension and determinants in Cameroon are crucial to inform efficient prevention and control policies. The authors carried out a cluster‐specific cross‐sectional survey in urban areas of the 10 regions of Cameroon to assess the prevalence and risk factors of hypertension in Cameroonian adults using the WHO STEPwise approach to Surveillance (STEPS). Sociodemographic data were collected and blood pressure and glycemia were measured using standardized methods. Participants were adults of both sexes aged 16 years or older. A total of 15,470 participants were surveyed. The age‐standardized prevalence rate of hypertension was 29.7%. The awareness rate was 14.1%. Independent correlates of hypertension included higher age, male sex, obesity, hyperglycemia, and living in the Savannah zone. The prevalence of hypertension is high in urban areas of Cameroon, with very low awareness. Prevention and control strategies should emphasize on improvement and vulgarization of population opportunistic screening and education.

Chronic heart failure, selected risk factors and co-morbidities among adults treated for hypertension in a cardiac referral hospital in Cameroon

Information on clinical characteristics of heart failure (HF) among Africans with hypertension is needed to help define the burden of hypertension in this population, but currently there is little data available.

Efficiency of an intervention package for arterial hypertension comprising telemanagement in a Cameroonian rural setting: The TELEMED-CAM study.

Introduction Sub-Saharan Africa has a disproportionate burden of disease and an extreme shortage of health workforce. Therefore, adequate care for emerging chronic diseases can be very challenging. We implemented and evaluated the effectiveness of an intervention package comprising telecare as a mean for improving the outcomes of care for hypertension in Rural Sub-Saharan Africa. Methods The study involved a telemedicine center based at the Yaounde General Hospital (5 cardiologists) in the Capital city of Cameroon, and 30 remote rural health centers within the vicinity of Yaoundé (20 centers (103 patients) in the usual care group, and 10 centers (165 patients) in the intervention groups). The total duration of the intervention was 24 weeks. Results Participants in the intervention group had higher baseline systolic (SBP) and diastolic (DBP) blood pressure, and included fewer individuals with diabetes than those in the usual care group (all p < 0.01). Otherwise, the baseline profile was mostly similar between the two groups. During follow-up, more participants in the intervention groups achieved optimal BP control, driven primarily by greater improvement of BP control among High risk participants (hypertension stage III) in the intervention group. Conclusion An intervention package comprising tele-support to general practitioners and nurses is effective in improving the management and outcome of care for hypertension in rural underserved populations. This can potentially help in addressing the shortage of trained health workforce for chronic disease management in some settings. However context-specific approaches and cost-effectiveness data are needed to improve the application of telemedicine for chronic disease management in resource-limited settings.

The spectrum of cardiac disease in the West Region of Cameroon: a hospital-based cross-sectional study

Background Cardiovascular disease is a growing public health problem in Africa. The extent of heart disease in Cameroon remains largely unknown. This study aimed at reporting the etiology of cardiac disease in a cardiologic clinic situated in a semi-urban area in the West region of Cameroon. Methods This is an analysis of echocardiographic diagnosis of cardiac disease done between July 2008 and October 2010 at the “Centre Medical de la Trinité” in the West region of Cameroon. Data included age, sex and echocardiographic findings. Results A total of 1252 patients presented with abnormal echocardiograms, 60.4% (n = 756) being female and 85.8% (n = 1074) aged over 50 years. Overall, the most important conditions were hypertensive heart disease (41.5%, n = 520) and cardiomyopathies (30.5%, n = 382). Among patients aged less than 10 years, congenital heart diseases were the most frequent (52.4%, n = 22), and rheumatic heart disease was the most important cardiac condition in patients aged 10 to 19 years (62.1%, n = 18) and those aged 20 to 39 years (53.3%, n = 8). Congenital heart diseases included persistent ductus arteriosus (27.6%, n = 8), tetralogy of Fallot (20.7%, n = 6) and inter-atria/interventricular communication (20.7%, n = 6). Conclusion Hypertension is the leading cause of cardiac disease among the elderly in our setting, emphasizing the necessity to strengthen the preventive strategies against hypertension in Cameroon. Rheumatic heart disease and congenital heart disease frequent in children and youths highlight the need of early detection and treatment of throat infections, and of routine cardiac surgery services in Cameroon.

Arterial Stiffness Impairment in Sickle Cell Disease Associated With Chronic Vascular Complications: The Multinational African CADRE Study.

Background: Although a blood genetic disease, sickle cell disease (SCD) leads to a chronic vasculopathy with multiple organ involvement. We assessed arterial stiffness in SCD patients and looked for associations between arterial stiffness and SCD-related vascular complications. Methods: The CADRE (Coeur Artères et Drepanocytose, ie, Heart Arteries and Sickle Cell Disease) study prospectively recruited pediatric and adult SCD patients and healthy controls in Cameroon, Ivory Coast, Gabon, Mali, and Senegal. Patients underwent clinical examination, routine laboratory tests (complete blood count, serum creatinine level), urine albumin/creatinine ratio measure, and a measure of carotid-femoral pulse wave velocity (cf-PWV) and augmentation index (AI) at a steady state. The clinical and biological correlates of cf-PWV and AI were investigated by using a multivariable multilevel linear regression analysis with individuals nested in families further nested in countries. Results: Included were 3627 patients with SCD and 943 controls. Mean cf-PWV was lower in SCD patients (7.5±2.0 m/s) than in controls (9.1±2.4 m/s, P<0.0001), and lower in SS-S&bgr;0 than in SC-S&bgr;+ phenotypes. AI, corrected for heart rate, increased more rapidly with age in SCD patients and was higher in SCD than in control adults. cf-PWV and AI were independently associated with age, sex, height, heart rate, mean blood pressure, hemoglobin level, country, and hemoglobin phenotype. After adjustment for these correlates, cf-PWV and AI were associated with the glomerular filtration rate and osteonecrosis. AI was also associated with stroke, pulmonary hypertension, and priapism, and cf-PWV was associated with microalbuminuria. Conclusions: PWV and AI are deeply modified in SCD patients in comparison with healthy controls. These changes are independently associated with a lower blood pressure and a higher heart rate but also with the hemoglobin phenotype. Moreover, PWV and AI are associated with several SCD clinical complications. Their prognostic value will be assessed at follow-up of the patients.

Patterns of cardiovascular disease in a group of HIV-infected adults in Yaoundé, Cameroon

BACKGROUND Cardiovascular disease is an increasingly important issue in human immunodeficiency viral (HIV)-infected individuals. There is dearth of information on the patterns of cardiovascular disease especially in sub-Saharan Africa (SSA) patients. This study reports on the clinical, biological, electrocardiographic and echocardiographic characteristics of a group of HIV-infected patients presenting with symptoms of heart disease in Yaoundé, Cameroon. METHODS This was a cross-sectional study conducted at the Yaoundé Central Hospital and Jamot Hospital. Consenting HIV-infected adults aged ≥18 years with symptoms suggestive of heart disease were consecutively recruited between February and July 2014. All participants underwent a complete clinical examination; biological analyses including CD4 cell counts, fasting blood glucose, and serum lipids, resting electrocardiography and cardiac ultrasound, and a venous ultrasound where necessary. RESULTS Forty four subjects (21 men) were included. Their mean age was 48 (SD 13) years. Thirty patients (68.2%) were in WHO clinical stages 3 and 4 of HIV infection, 27 (61.4%) had a CD4 cell count <200/mm(3), and 31 (70.5%) were on antiretroviral therapy (ART). Hypertension (43.2%, n=19) was the most frequent cardiovascular risk factor; and dyslipidemia which was found in 17 subjects (38.6%) was significantly associated with ART (48.4% vs. 15.4%, P=0.04). Only men where smokers (23% vs. 0%, P=0.019). Exertional dyspnea (86.4%, n=38) and cough (59.1%, n=26) were the most frequent symptoms, and the clinical presentation was dominated by heart failure (75%, n=33). The most frequent echocardiographic abnormalities were pericardial effusion (45.5%, n=20) and dilated cardiomyopathy (22.7%, n=10). Dilated cardiomyopathy was significantly associated with CD4 cell counts <200/mm(3) (100%, P=0.003). Primary pulmonary hypertension (PH) rate was 11.4% (n=5) and all cases occurred at CD4 cell counts ≥200/mm(3) (P=0.005). The most frequent electrocardiographic abnormalities were abnormal repolarization (59%, n=26) and sinus tachycardia (56.8%, n=25). CONCLUSIONS Cardiovascular risk factors such as hypertension and dyslipidemia are common in HIV-infected adults with heart disease in our milieu. Advanced HIV infection in adults is associated with a high rate of symptomatic heart disease, mostly effusive pericarditis and dilated cardiomyopathy. Primary PH occurred in less advanced HIV disease.