Detection and characteristics of hypertension patients admitted in 37 cardiology departments from 17 Sub-Saharan African countries

Background

High blood pressure (BP) is a major risk factor for several common cardiovascular (CV) disease such as stroke, heart failure or chronic kidney disease. The Sub-Saharan Africa (SSA) should face the highest rate of hypertension worldwide with an overall prevalence estimation of 46%. Due to scarce resources and inadequate healthcare provision, SSA have scarce hard data on treatment and control of high BP.

Purpose

To assess the detection and characteristics of hypertension patients admitted in hospitalizations 17 SSA countries

Methods

We conducted a transversal and longitudinal study in CV department of 37 hospitals from 23 cities in 17 SSA countries (10 low income: Niger, Guinea, Benin, Mali, Democratic Republic of the Congo, Tchad, Burkina Faso, Togo, Burundi, Ethiopia and 7 middle income: Cote d'Ivoire, Senegal, Cameroon, Congo, Soudan, Mauritania, Gabon). The February study was designed by a multidisciplinary collaborative team of epidemiologists, pharmacists and cardiologists from Africa and France. This ongoing observatory included all inpatients in February from each year since 2016. Data including socio-demographic and clinical characteristics, causes of admission, clinical, biological, complementary examinations, treatments, length of stay and discharge diagnosis were collected by the investigating physicians. Hypertension and severity of hypertension were defined according to 2018 ESC/ESH guidelines and BP was measured twice using standardized method. All analyses were performed through scripts developed in the R software (4.0.3 (2020-10-10))

Results

The study involved 4360 patients. Hypertension was measured on 1906 (43.7%) patients at admission. Proportion of patients with high BP in hospital increased from 42.2% in 2016 to 52.2% in 2021 (p<0.05) and differed significantly across countries from 77.6% in Niger to 100% in Chad. Among hypertensive patients, men represented 59.6% of patients and mean of age was 59±15.1 years. Overall, 61.4% of patients were from low income countries. The mains causes of admission among hypertensive patients were heart failure (37.8%) and stroke (18.9%). Average of systolic BP was 159±29.3 mmHg and average of diastolic BP was 96.7±16mmHg. Overall, 760 (40.3%), 525 (27.8%) and 602 (31.9%) had grade 1, grade 2 and grade 3 hypertension respectively. History of CV disease was observed in 51.5% of patients. Thus, 70.4% of patients had at least one CV risk factor other than hypertension. Angiotensin converting enzyme inhibitors and diuretics was prescribed in 56.9% and 55.8% of patients respectively. The average amount of antihypertensive drugs prescribed in hospital was 2.09±1.18. Overall, 237 (12.4%), 295 (15.5%), 640 (33.6%) and 734 (38.5%) received respectively no drug, monotherapy, two-drug strategies and three and more drug strategies.

Conclusion

In patients admitted in cardiology departments, hypertension is a huge burden in SSA.

Funding Acknowledgement

Type of funding sources: None.

Long-term prognosis of patients with permanent cardiac pacemaker indication in three referral cardiac centers in Cameroon: Insights from the National pacemaker registry

BACKGROUND

There is evidence that cardiac pacemakers improve symptoms and quality of life in patients with severe bradycardia. Globally, the number of pacemaker implantations is on the rise. However, the associated high-cost limits pacemaker's accessibility in low resource settings. This study aimed to investigate access to pacemakers and the long-term outcome of patients requiring a pacemaker.

METHOD

We conducted a cohort study in 03 health care structures in Cameroon. Participants aged at least 18 years with indication for a permanent pacemaker between January 2010 and May 2016 were included. Clinical profile, electrocardiography, pacemaker implantation parameters were recorded. Long-term survival was studied by event-free analysis using the Kaplan-Meier method.

RESULTS

In total, 147 participants (mean age 67.7±13.7 years, female 58.5%) were included. Fatigue (78.7%), dyspnoea (77.2%), dizziness (47.1%) and palpitations (40.4%) were the main symptoms while syncope was present in 35.7% of patients. The main indication for cardiac pacemaker was atrioventricular block (85.3%). Forty (27.2%) could not be implanted with 34 (85%) of participants highlighting cost of intervention as main reason. VVIR was the main mode of stimulation (70.5%). Of 125 patients in which follow-up was ascertained, 17(13.5%) died after a median survival time of 2.8 years post diagnosis [IQR: 1.8-4.2]. The survival curve was better in participants with a pacemaker with a Hazard ratio of 2.7 [CI: 1.0-7.3, P=0.045].

CONCLUSION

Our patients with severe heart blocks presented late and more than a quarter did not have access to pacemaker but its implantation multiplied the survival rate by 2.7 times at approximately 3 years post diagnosis. Improving early detection of heart blocks and access to cardiac pacing to reduce mortality shall be a key future priority.

P3344Research network in Africa (RNA): observatory of hospitalizations in cardiology departments in 14 African countries (FEBRUARY Study: 2016, 2017 and 2018)

Background

Epidemiological transition in the developing world has resulted in a shift from infectious to non-communicable diseases as leading causes of morbidity and mortality, cardiovascular (CV) disease (CVD) is the first cause of death in Africa. However, data regarding the characteristic of patients with CVD are scarce, especially in Sub-Saharan Africa.

Purpose

We built an observatory recording the characteristics of all patients admitted to hospital in CV departments and hospital care components in Sub-Saharan Africa (FEBRUARY Study).

Methods

We conducted a transversal and longitudinal study in CV departments of 29 hospitals from 14 African countries. FEBRUARY study was designed by a multidisciplinary collaborative team of epidemiologists, pharmacists and cardiologists from Africa and France. This ongoing observatory included all patients admitted in hospitalization during the month of February every year since 2016 and will continue every year. Data including socio-demographic and clinical characteristics, causes of admission, clinical, biological, complementary examinations, treatments, length of stay and discharge diagnosis were collected by the investigating physicians.

Results

Overall 2680 patients were admitted to hospital in February 2016 (n=736), 2017 (n=967), and 2018 (n=987) in CV departments from 14 countries: Benin, Burkina Faso, Burundi, Cameroon, Congo, Côte d'Ivoire, Gabon, Guinea, Mali, Niger, Dem. Rep of The Congo, Senegal, Togo and Sudan (figure). Men represented 58,8%. Mean age of age was 54 years and Women 52 years. The mean length of stay was 9 days, and death rate 10,1%. The main cause of admission was cardiac failure (40,3%) followed by acute coronary syndrome (10.1%) and stroke (9,3%). Among CV risk factors, high blood pressure, sedentary behavior, diabetes, active tobacco consumption and dyslipidemia were present in 46%, 19%, 13%, 11% and 6% of patients, respectively.

In a longitudinal analysis, hospital admission due coronary syndrome increased from 7% in 2016 to 10.5% in 2018 (p for trend = 0.03). Length of hospital stay and rate of hospital death remain stable.

Hospitalizations by country (FEBRUARY)

Conclusion

The FEBRUARY observatory is an important tool to describe cardiovascular characteristics of patients in transversal analysis, but also the longitudinal evolution over the coming years in Sub-Saharan Africa.

P4567Factors associated with poor adherence to medication among hypertensive patients in twelve low and middle income sub-Saharan countries

Background

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.

Purpose

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.

Methods

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.

Figure 1. Percentage of patients according to their adherence level by patient wealth index stratified by country-level income.

Sickle cell retinopathy and other chronic complications of sickle cell anemia: A clinical study of 84 Sub-Saharan African cases (Cameroon)

OBJECTIVE

Sickle retinopathy is a severe complication of sickle cell disease than can lead to blindness. We aim to describe the epidemiology of sickle retinopathy in homozygous sickle cell (SS) African patients and to analyze its association with non-ophthalmologic disease complications of sickle cell anemia.

METHODS

We conducted a nested study within the CADRE cohort in Cameroon. Eighty-four consecutive SS outpatients, aged 10 years and older, with no visual symptoms, underwent an ophthalmologic examination. Mean age was 23±10 years. Clinical and biological features were compared between patients with and without sickle retinopathy. We compared the prevalence of the clinical complications and main biological characteristics in patients with and without sickle retinopathy using a univariate logistic regression. The same analysis was used to compare the patients with non-proliferative sickle retinopathy to those with proliferative sickle retinopathy. Statistical analyses were done using the R software (version 3.1.2).

RESULTS

Fifty-two patients (62%) displayed sickle retinopathy, among them 23 (27%) had a non-proliferative sickle retinopathy, and 29 (35%) had proliferative sickle retinopathy. Patients with proliferative sickle cell retinopathy had a mean age of 28±11 years. Sickle retinopathy was associated with higher hemoglobin level (P=0.047) and fewer leg ulcers (P=0.018). Proliferative SR was associated with increasing age (P=0.008) and male sex (P=0.025) independently of the hemoglobin level.

CONCLUSIONS

Sickle retinopathy is particularly frequent in sub-Saharan sickle cell SS patients, which advocates for early systematic screening.

Assessment of cardiac function in children with congenital adrenal hyperplasia: a case control study in Cameroon

BACKGROUND

High level of androgens found in congenital adrenal hyperplasia (CAH) seems to have a deleterious effect on heart function. We therefore evaluate cardiac function of children with CAH in comparison with a healthy group.

METHODS

We carried out a case-control study in the single endocrinology unit of the Mother and Child Center of Chantal Biya's Foundation. Cases were matched for age and genotypic sex to 2 healthy controls. We analyzed the ejection fraction (LVEF), fractional shortening and left ventricular mass; output and cardiac index; E and A waves velocities, E/A ratio and the mitral deceleration time and diameter of the left atrium; tricuspid annular plane systolic excursion and pulmonary artery systolic pressure were also measured.

RESULTS

We included 19 patients with a median age of 6.26 ± 3.75 years and 38 controls stackable distribution. The left ventricular mass of cases was greater than that of controls. A case of reversible cardiomyopathy on hormone replacement therapy was found. For the cases, the average ejection fraction was 71.95 ± 7.88%; the average fractional shortening was 40.67 ± 7.02%. All these values ​​were higher than those of controls, although the difference was not statistically significant. Diastolic left ventricular function was more impaired among the cases. Right ventricular function was similar in both groups. These abnormalities were highly correlated to the late age at diagnosis and duration of treatment.

CONCLUSION

This study shows an altered cardiac function in CAH compared to healthy control and highlights importance of an early diagnosis of cases, a tight control of androgens levels and a regular monitoring of cardiac function.

Strengthening human resources for health through multisectoral approaches and leadership: the case of Cameroon

PROBLEM

Cameroon has a severe shortage of human resources for health (HRH) and those that are available are concentrated in urban areas.

APPROACH

As the result of a national emergency plan for the years 2006-2008, innovative strategies and a multisectoral partnership - led by the Ministry of Public Health and supported by diverse national and international organizations - were developed to address the shortages and maldistribution of HRH in Cameroon.

LOCAL SETTING

At the time that the emergency plan was developed, Cameroon had health services of poor quality, an imbalance between HRH training and employment, a maldistribution of HRH between urban and rural areas and a poor allocation of financial resources for HRH. It also lacked an accreditation system for use in the training of health workers.

RELEVANT CHANGES

Between 2007 and 2009, the number of active health workers in Cameroon increased by 36%, several new institutions for higher education in health care and training schools for paramedical staff and midwives were opened, and a national strategy for universal health coverage was developed.

LESSONS LEARNT

In the improvement of HRH, strong leadership is needed to ensure effective coordination and communication between the many different stakeholders. A national process of coordination and facilitation can produce a consensus-based view of the main HRH challenges. Once these challenges have been identified, the stakeholders can plan appropriate interventions that are coordinated, evidence-based and coherent.

Efficacy of newer versus older antihypertensive drugs in black patients living in sub-Saharan Africa

To address the epidemic of hypertension in blacks born and living in sub-Saharan Africa, we compared in a randomised clinical trial (NCT01030458) single-pill combinations of old and new antihypertensive drugs in patients (30-69 years) with uncomplicated hypertension (140-179/90-109 mm Hg). After ≥4 weeks off treatment, 183 of 294 screened patients were assigned to once daily bisoprolol/hydrochlorothiazide 5/6.25 mg (n=89; R) or amlodipine/valsartan 5/160 mg (n=94; E) and followed up for 6 months. To control blood pressure (<140/<90 mm Hg), bisoprolol and amlodipine could be doubled (10 mg per day) and α-methyldopa (0.5-2 g per day) added. Sitting blood pressure fell by 19.5/12.0 mm Hg in R patients and by 24.8/13.2 mm Hg in E patients and heart rate decreased by 9.7 beats per minute in R patients with no change in E patients (-0.2 beats per minute). The between-group differences (R minus E) were 5.2 mm Hg (P<0.0001) systolic, 1.3 mm Hg (P=0.12) diastolic, and 9.6 beats per minute (P<0.0001). In 57 R and 67 E patients with data available at all visits, these estimates were 5.5 mm Hg (P<0.0001) systolic, 1.8 mm Hg (P=0.07) diastolic and 9.8 beats per minute (P<0.0001). In R compared with E patients, 45 vs 37% (P=0.13) proceeded to the higher dose of randomised treatment and 33 vs 9% (P<0.0001) had α-methyldopa added. There were no between-group differences in symptoms except for ankle oedema in E patients (P=0.012). In conclusion, new compared with old drugs lowered systolic blood pressure more and therefore controlled hypertension better in native African black patients.

Prevalence and determinants of electrocardiographic abnormalities in sub-Saharan African individuals with type 2 diabetes

Aim

This study assessed the prevalence and determinants of electrocardiographic abnormalities in a group of type 2 diabetes patients recruited from two referral centres in Cameroon.

Methods

A total of 420 patients (49% men) receiving chronic diabetes care at the Douala General and Yaoundé Central hospitals were included. Electrocardiographic abnormalities were investigated, identified and related to potential determinants, with logistic regressions.

Results

The mean age and median duration of diagnosis were 56.7 years and four years, respectively. The main electrocardiographic aberrations (prevalence %) were: T-wave abnormalities (20.9%), Cornell product left ventricular hypertrophy (16.4%), arrhythmia (16.2%), ischaemic heart disease (13.6%), conduction defects (11.9%), QTc prolongation (10.2%) and ectopic beats (4.8%). Blood pressure variables were consistently associated with all electrocardiographic abnormalities. Diabetes-specific factors were associated with some abnormalities only.

Conclusions

Electrocardiographic aberrations in this population were dominated by repolarisation, conduction defects and left ventricular hypertrophy, and were more related to blood pressure than diabetes-specific factors.

Achieving blood preSsure goals sTudy in uncontrolled hypeRtensive pAtients treated with a fixed-dose combination of ramipriL/hydrochlorothiazide: the ASTRAL study

Background

Hypertension is a common cardiovascular disease, affecting adults worldwide and it accounts for up to 30% of all deaths. The need for better control of arterial hypertension justifies observational studies designed to better understand the real-life management of hypertensive patients. The ASTRAL study was primarily designed to evaluate the percentage of hypertensive patients achieving blood pressure goals after eight weeks of treatment with a fixed-dose combination of ramipril/hydrochlorothiazide (HCTZ).

Methods

The study was a multi-centre, non-comparative, open-label, observational study conducted in 36 centres in five sub-Saharan African countries, namely Cameroon, Congo Brazzaville, Democratic Republic of Congo (DRC), Madagascar and Nigeria. Four hundred and forty-nine men and women 18 years of age or older with hypertension not controlled by an ACE inhibitor, a diuretic or any other monotherapy or anti-hypertensive combination not containing a diuretic in a fixed dose were considered eligible for inclusion in this eight-week study. The study consisted of three visits, visit one (V1) at baseline, visit two (V2) after four weeks and visit three (V3) after eight weeks.

Results

The mean age of the patients was 54.7 ± 11.7 years (20–90 years) and most were categorised by the WHO criteria as either overweight or obese (71.6%). After four and eight weeks of treatment with the study drug, systolic and diastolic blood pressures significantly changed from baseline: –24.7/–14.2 mmHg (p < 0.001) and –31.7/–17.9 mmHg (p < 0.001), respectively. There were 60.2% of the non-diabetics on prior monotherapy who, at eight weeks, fulfilled the primary blood pressure goal for SBP and DBP, versus 26.5% of the diabetic patients, also on monotherapy. Few adverse events were reported, with facial oedema and dry cough recurring twice in two patients.

Conclusion

Fixed-dose combination of ramipril/HCTZ is therefore effective, tolerable and has a good safety profile for blood pressure control in black Africans.

[Cardiac surgery in Cameroon. Results at one year of the pilot phase]

In the framework of implementation of his national program for control and prevention of cardiovascular diseases, Cameroonian government has set up a cardiac surgery project. We report in this manuscript results of one year follow up of the patients operated during the pilot phase. From September 22 till 26, 2008, 11 patients have been operated in Cameroun. Surgical procedures were 5 mitral mechanic valve replacement, 2 aortic mechanic valve replacement, 1 atrial septal defect closure, 2 pace maker implantation. No intrahospital death was observed. One patient died at 11th month after the operation due to mitral valve thrombosis and attributed to lack of compliance. One patient presented low cardiac output, pneumonia and a pleural effusion. 2 patients presented 2 minor complications consisting of pericarditis and superficial wound infection. The results of the pilot phase of cardiac surgery in Cameroon are effective. However, the sustainability of the program require human, material capacity building, and funding mechanism as well.

[Cardiovascular emergencies in Subsaharan Africa]

BACKGROUND

The increasing prevalence of cardiovascular diseases in subsaharan Africa and their related mortality and morbidity have been established. A large number of them present as emergencies. The purpose of this first multicentric study was to assess the causes, management and outcome of cardiovascular emergencies in savannah and forest environments.

METHODS

A total of 665 patients were included from seven participating centers in seven countries: 417 were classified as belonging to the savannah zone (Dakar, Nouakchott, Ouagadougou, N'djamena) whereas 248 patients were from the forest zone (Abidjan, Libreville, Yaounde). Patients were examinated by one or several cardiologists. Statistical analysis was performed by the Medical Statistic Unit of the Hopital Nord, Marseille (France).

RESULTS

There were more men (53.4%) than women (46.6%). 77.7% of the patients lived in urban areas. Most of them had low or very low incomes. Patients reached the hospitals in ambulances only in 6.2% of cases. The remaining others were transported by routine urban vehicle or bicycle or ambulation. The mean delay between the onset of symptoms and the arrival to the emergency unit was 6.8 days. Three immediate situations were preponderant: severe hypertension (32.2%), heart failures NYHA IV (27.5%), stroke (20.3%). Underlying conditions were: mainly chronic hypertension (52.3%), cardiomyopathies (20.6%), valvular heart diseases (11.1%). Coronary heart diseases were rare (6.1%). The observed mortality was 21.2% without any differences in age groups. The most common emergencies resulting in death included: stroke (31.9%), vascular collapses (18.4%), pulmonary embolism (9.2%). The patients from the savannah zone were younger, more often classified in the low or average socioeconomic level. Hypertension was more frequent in forest zones. Valvular heart diseases were more frequent in savannah. Cardiomyopathies were comparable in both zones. Coronary heart disease was slightly more common in the savannah area.

DISCUSSION

Compared with patients from western countries, the African patients are younger because some diseases affect young people like rheumatic heart disease or postpartum and infectious cardiomyopathies. The difficulties to reach health care facilities made the outcome more severe. Hypertension and valvular heart disease deserve priority in preventive strategy. Cardiomyopathies have to be studied to precise their causes. Finally, the management of cardiovascular emergencies needs a special care in the hospitals owing to their increasing frequency and their severity.

[A new look at adult chronic heart failure in Africa in the age of the Doppler echocardiography: experience of the medicine department at Yaounde General Hospital]

OBJECTIVE

Heart failure is a frequent and severe condition in Africa, yet few African data are available that take into account modern advances like echocardiography in diagnosis. This study aimed to characterize the epidemiological, clinical, etiologic and therapeutic features of heart failure at Yaounde General Hospital.

METHODS

A descriptive study was carried from October 1998 to November 2001. One hundred and sixty-seven patients presenting with clinical and echocardiographic signs of heart failure were included, among which 99 men and 68 women, mean aged 57 years.

RESULTS

Heart failure was the reason for 5,77% of all hospital admissions. Rehospitalisation rate was 8,33%, the prevalence 30% and overall mortality was 9,03%. 44% of patients were in class III of the NYHA and 7% in class IV. Dyspnoea was a constant symptom (95,20%); hepatomegaly was the most frequent physical finding (41,92%). Cardiac cavities were dilated and left ventricular ejection fraction was low in patients with systolic (70%) and combined (20%) dysfunction. Isolated diastolic heart failure accounted for 10% of cases. Main aetiologies were: Hypertension (54,49%), cardiomyopathies (26,34%) and valvular heart diseases (24,55%). Ischaemic heart disease was the fifth aetiology (2,39%). Medical treatment consisted of loop diuretics (90%), angiotensin-converting enzyme inhibitor (64,7%), digoxin (30,5%) and beta blockers (19,8%).

CONCLUSIONS

The clinical syndrome of heart failure constitutes a major public health problem in Cameroon. Echocardiography is of paramount importance in confirming the diagnosis and precising its aetiology. Preventive and public health strategies need to be defined according to the local characteristics.

[Venous thromboembolism in Cameroon (report of 18 cases)]

The purpose of this report was to describe clinical and ultrasound findings associated with venous thromboembolism of the lower extremities and pulmonary embolism observed in our department with special emphasis on the utility of venous ultrasound in the diagnosis of venous thromboembolism. Between January 1, 1998 and December 31, 1999, a total of 47 venous ultrasound procedures were carried out according to the standard technique using a Logic 400 MD system (General Electric). Deep venous thrombosis was diagnosed in 18 cases (38.3%). There were 10 men and 8 women with a mean age of 46 years (range, 24 to 71 years). Thrombosis involved the internal saphenous, popliteal, or sural vein in 12 cases, the common or deep femoral vein in 4, and the external iliac vein in 2. The most common risk factors observed in our series were surgery, predisposing conditions, history of venous thrombosis and morbid obesity (66.8% of case). Prolonged periods of bed confinement and neoplasm (lower extremity Kaposi's disease) were more uncommon (22.2%). Pulmonary embolism occurred during the observation period in six cases (33.3%) including 3 (50%) that were fatal. Based on these findings it can be concluded that although its incidence is relatively low in black African patients at risk, thromboembolic disease is often fatal and requires routine preventive treatment using heparin.

[Ultrasonic demonstration of carotid atherosclerosis in black Cameroonian adults with cardiovascular risk]

The objective of this study was to determine the prevalence of carotid atherosclerosis in black Cameroonian adults presenting cardiovascular risk factors (CVRF). It was based on 77 subjects over the age of 40 years (50 men and 27 women) with at least one major CVRF, such as hypertension (HT), smoking, dyslipidaemia or diabetes mellitus. Obesity [body mass index (BMI), waist/hips ratio (W/H)] and hyperuricaemia were also taken into account. Duplex ultrasound examination of the carotid arteries was performed with a Siemens apparatus equipped with a 7.5 MHz transducer array. An atheromatous plaque was defined as medio-intimal thickening > or = 1.5 mm, with either protrusion or hyperechogenicity. Risk factors were distributed as follows in our serie: HT: 82%, Obesity: 49% (W/H) and 32% (BMI); Diabete: 32%; Smoking: 23%; Hyperuricaemia: 21%; Hypercholesterolaemia: 13%. 19 subjects (25%) (12 men and 7 women with a mean age of 63 years) presented one or more atheromatous plaques in the carotid arteries. Hyperuricaemia and hypercholesterolaemia were significantly correlated with the presence of plaques, with a marked tendency in subjects over the age of 70. In this study, hyperuricaemia and advanced age appeared to be independent arterial risk factors on multivariate analysis. In conclusion, our data show that carotid atherosclerosis does exist in our populations, especially in elderly subjects with cardiovascular risk factors. The particular role of hyperuricaemia as a predictive factor of atheromatous plaques in black Cameroonian subjects needs to be defined.

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.

Circadian rhythm of hypertensives in a Cameroon population: a pilot study

The present study was designed to determine diurnal blood pressure (BP) variations in black hypertensive Africans in Cameroon. Also the study assessed sex differences associated with ambulatory BP measurements in this black population. A total of 69 adult Cameroonians aged 25-55 years, who attended a hypertensive clinic in Yaounde, Cameroon, were recruited on a voluntary basis. The mean ages of the males and females were 48.9 and 45.8 years, respectively. Ambulatory BP monitoring was recorded with Spacelabs ICR Model 5300 ambulatory BP monitoring systems. SBP, DBP and heart rate were measured every 30 min over a 24 h period. There were no significant mean differences observed between males and females on 24 h, daytime or night-time BPs. Among the Cameroonians, 31.7% (20 of 63) of the study population were 'non-dippers'. There were no sex difference for dippers compared with non-dippers. Significant nocturnal declines were noted for SBP, DBP, heart rate and mean arterial pressure. The results of the present study reveal that in this select Cameroonian population, there exists a nocturnal decline in BP.

Distribution of anthropometric variables and the prevalence of obesity in populations of west African origin: the International Collaborative Study on Hypertension in Blacks (ICSHIB)

A survey of the prevalence of hypertension and associated risk factors including obesity was carried out among persons of West African heritage currently living in societies at different stages of social, economic and technological development. We present here the distribution of several anthropometric variables and the prevalence of obesity in these populations. Using a standard protocol with centralized training of field staff, 7,439 men and women aged 24 to 75 from six multinational sites were recruited and examined. Although men were taller, women were more obese across sites. Body mass index (BMI) and consequently the prevalence of overweight and obesity increased with westernization from rural African subsistence farming communities to suburban Chicago. Average BMI increased with age until about age 54, and then began to decline or at least level off. The mean BMI for African-American men and women was 27.1kg/m2 and 30.8kg/m2, respectively. Men displayed high levels of centripetal fatness, measured as the waist-to-hip ratio (WHR), compared to the women across site. Based on the US Department of Agriculture guidelines, 22.6% and 56.9% of the African-American men and women had elevated WHR. Although account must be taken of the important contribution of an individual's genetic background, this multinational study of persons with similar heritage clearly shows the potent impact of current environmental factors on the distribution and level of obesity.