A systematic overview of prospective cohort studies of cardiovascular disease in sub-Saharan Africa

Characteristics and outcomes of patients with symptomatic chronic myocardial injury in a Tanzanian emergency department: A prospective observational study

BACKGROUND

Chronic myocardial injury is a condition defined by stably elevated cardiac biomarkers without acute myocardial ischemia. Although studies from high-income countries have reported that chronic myocardial injury predicts adverse prognosis, there are no published data about the condition in sub-Saharan Africa.

METHODS

Between November 2020 and January 2023, adult patients with chest pain or shortness of breath were recruited from an emergency department in Moshi, Tanzania. Medical history and point-of-care troponin T (cTnT) assays were obtained from participants; those whose initial and three-hour repeat cTnT values were abnormally elevated but within 11% of each other were defined as having chronic myocardial injury. Mortality was assessed thirty days following enrollment.

RESULTS

Of 568 enrolled participants, 81 (14.3%) had chronic myocardial injury, 73 (12.9%) had acute myocardial injury, and 412 (72.5%) had undetectable cTnT values. Of participants with chronic myocardial injury, the mean (± sd) age was 61.5 (± 17.2) years, and the most common comorbidities were CKD (n = 65, 80%) and hypertension (n = 60, 74%). After adjusting for CKD, thirty-day mortality rates (38% vs. 36%, aOR 1.03, 95% CI: 0.52-2.03, p = 0.931) were similar between participants with chronic myocardial injury and those with acute myocardial injury, but significantly greater (38% vs. 13.6%, aOR 3.63, 95% CI: 1.98-6.65, p<0.001) among participants with chronic myocardial injury than those with undetectable cTnT values.

CONCLUSION

In Tanzania, chronic myocardial injury is a poor prognostic indicator associated with high risk of short-term mortality. Clinicians practicing in this region should triage patients with stably elevated cTn levels in light of their increased risk.

Scaling-up and scaling-out the Systems Analysis and Improvement Approach to optimize the hypertension diagnosis and care cascade for HIV infected individuals (SCALE SAIA-HTN): a stepped-wedge cluster randomized trial

BACKGROUND

Undiagnosed and untreated hypertension is a main driver of cardiovascular disease and disproportionately affects persons living with HIV (PLHIV) in low- and middle-income countries. Across sub-Saharan Africa, guideline application to screen and manage hypertension among PLHIV is inconsistent due to poor service readiness, low health worker motivation, and limited integration of hypertension screening and management within HIV care services. In Mozambique, where the adult HIV prevalence is over 13%, an estimated 39% of adults have hypertension. As the only scaled chronic care service in the county, the HIV treatment platform presents an opportunity to standardize and scale hypertension care services. Low-cost, multi-component systems-level strategies such as the Systems Analysis and Improvement Approach (SAIA) have been found effective at integrating hypertension and HIV services to improve the effectiveness of hypertension care delivery for PLHIV, reduce drop-offs in care, and improve service quality. To build off lessons learned from a recently completed cluster randomized trial (SAIA-HTN) and establish a robust evidence base on the effectiveness of SAIA at scale, we evaluated a scaled-delivery model of SAIA (SCALE SAIA-HTN) using existing district health management structures to facilitate SAIA across six districts of Maputo Province, Mozambique.

METHODS

This study employs a stepped-wedge design with randomization at the district level. The SAIA strategy will be "scaled up" with delivery by district health supervisors (rather than research staff) and will be "scaled out" via expansion to Southern Mozambique, to 18 facilities across six districts in Maputo Province. SCALE SAIA-HTN will be introduced over three, 9-month waves of intensive intervention, where technical support will be provided to facilities and district managers by study team members from the Mozambican National Institute of Health. Our evaluation of SCALE SAIA-HTN will be guided by the RE-AIM framework and will seek to estimate the budget impact from the payer's perspective.

DISCUSSION

SAIA packages user-friendly systems engineering tools to support decision-making by frontline health workers and to identify low-cost, contextually relevant improvement strategies. By integrating SAIA delivery into routine management structures, this pragmatic trial will determine an effective strategy for national scale-up and inform program planning.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05002322 (registered 02/15/2023).

To Remind or Not to Remind During Recruitment? An Analysis of an Online Panel in Germany

Objective: To explore the role of reminders in recruiting and maintaining participation in an online panel. Methods: 50,045 individuals from five German federal states were invited by regular mail to participate in the online study "Health-Related Beliefs and Healthcare Experiences in Germany." Those who did not respond to the first attempt received a postal reminder. Comparisons of sociodemographic characteristics and responses were made between first-attempt respondents and those who enrolled after the second letter. Results: After the initial letter, 2,216 (4.4%, 95%CI: 4.3%-4.6%) registered for the study; after a reminder 1,130 (2.5%, 2.3%-2.6% of those reminded) enrolled. Minor sociodemographic differences were observed between the groups and the content of the responses did not differ. Second-attempt respondents were less likely to participate in subsequent questionnaires: 67.3% of first-attempt vs. 43.3% of second-attempt respondents participated in their fourth survey. Recruitment costs were 79% higher for second-attempt respondents. Conclusion: While reminders increased the number of participants, lower cost-effectiveness and higher attrition of second-attempt respondents support the use of single invitation only for studies with a similar design to ours when the overall participation is low.

Undiagnosed hypertension and its associated factors in Ethiopia: A systematic review and meta-analysis

Background and Aims

Early identification and treatment of hypertension could lower the risk of cardiovascular diseases; which share the largest proportion of death. The findings of previous studies done in Ethiopia on undiagnosed hypertension were inconsistent. Therefore, this systematic review and meta-analysis aimed to assess the prevalence and associated factors of undiagnosed hypertension among adults in Ethiopia.

Methods

A protocol with registration number CRD42023395445 was registered to Prospective Register of Systematic Reviews (PROSPERO). A comprehensive search of observational studies done on undiagnosed hypertension was identified in PubMed, Google Scholar, Cochrane Library, Hinari databases, and other sources available until January 10, 2023. The quality of the identified studies using the set criteria and necessary data was extracted and exported to R version 4.2.3 and STATA version 15.0 for analysis. The pooled prevalence of undiagnosed hypertension and its associated factors were identified. The risk of bias was evaluated using a funnel plot and Egger's test. The findings were presented using tables, figures, and statements. This study was not funded by any organization.

Results

Eleven studies having 6132 participants were included in the analysis. The pooled prevalence of undiagnosed hypertension was 21% (95% confidence interval [CI]: 16-27). In subanalysis, according to the American Heart Association ( ≥ 130/80 mmHg), the pooled prevalence was 29% (95% CI: 18-40). However, according to the International Society of Hypertension ( ≥ 140/90), the pooled prevalence was 16% (95% CI: 13-20).Sex (AOR = 2.49, 1.48-3.49), age ≥55 years (AOR = 2.68, 1.16-4.21), alcohol drinking (AOR = 2.68, 1.68-3.69), body mass index ≥25 kg/m2 (AOR = 2.62, 1.77-3.48), and high triglyceride levels (AOR = 1.87, 1.22-2.51) were significantly associated with it.

Conclusion

In Ethiopia, about one in five adults ≥ 18 years has undiagnosed hypertension; therefore raising public awareness for medical checkups, early hypertension detection, and treatment is suggested. However, these findings cannot be generalized to pediatrics.

Reducing Dietary Sodium Intake among Young Adults in Ghana: A Call to Action

The positive association between excessive dietary sodium intake, hypertension, and cardiovascular disease (CVD) has been widely investigated in observational studies and clinical trials. Reducing sodium intake is a proven strategy to prevent hypertension and the onset of CVD, a major cause of morbidity and mortality globally. Africa has the youngest population globally, which is key to the continent's sustainable development. However, in Africa, the epidemics of hypertension and CVD negatively impact life expectancy and economic growth. Ghana, like other African countries, is no exception. The factors contributing to the increasing burden of CVD and excessive sodium consumption are multi-faceted and multi-level, including individual lifestyle, neighborhood and built environments, and socio-economic and health policies. Thus, the implementation of evidence-based interventions such as the World Health Organization Best Buys that target the multi-level determinants of sodium consumption is urgently needed in Ghana and other African countries. The aim of this commentary is to highlight factors that contribute to excessive sodium consumption. Second, the commentary will showcase lessons of successful implementation of sodium reduction interventions in other countries. Such lessons may help avert CVD in young adults in Ghana and Africa.

Homoarginine and blood pressure: a 10-year prospective relationship in normotensives

Nitric oxide plays a major role in the regulation of blood pressure, and impaired nitric oxide bioavailability contributes to the development of hypertension (HT). Various factors may contribute to nitric oxide bioavailability-including availability of the substrate for nitric oxide synthesis, L-arginine and its homolog L-homoarginine. We investigated whether blood pressure after 10 years associates with baseline L-homoarginine in participants who remained normotensive (NT) or developed HT, respectively. Data from the South African leg of the Prospective Urban and Rural Epidemiology study, performed in the North-West Province, were used. We investigated participants who either remained NT (N = 166) or who developed HT (N = 166) over 10 years. Blood pressure was measured with validated OMRON devices and serum L-homoarginine was analyzed with liquid chromatography-tandem mass spectrometry. L-homoarginine levels were similar at baseline (p = 0.39) and follow-up (p = 0.93) between NT and hypertensive groups. In the group that remained NT after 10 years, baseline L-homoarginine correlated positively with follow-up brachial systolic blood pressure (adj.R² = 0.13; β = 0.33; p = 0.001), brachial pulse pressure (adj.R² = 0.15 β = 0.40; p = 0.001), and central pulse pressure (adj.R² = 0.20; β = 0.30; p = 0.003). No significant associations were found in the group that developed HT after 10 years. We found a positive, independent association between blood pressure and L-homoarginine in a group that remained NT, but not in a group that developed HT after 10 years. This may suggest a protective role for L-homoarginine to maintain normal blood pressure, but only to a certain level. Once HT develops other factors may overshadow the protective effects of L-homoarginine.

Hypertension incidence among middle-aged and older adults: findings from a 5-year prospective study in rural South Africa, 2010-2015

OBJECTIVES

There is a scarcity of longitudinal cohort studies in sub-Saharan Africa to understand the epidemiology of cardiovascular disease as a basis for intervention. We estimated incident hypertension and associated sociodemographic, health and behavioural risk factors in a population aged 40 years and older over a 5-year period.

DESIGN

We assessed the association between incident hypertension and sociodemographic, health and behavioural factors using Poisson regression. We adjusted for non-response in 2015 using inverse probability sampling weights from a logistic regression including sex and age at baseline.

SETTING

Rural South Africa.

PARTICIPANTS

We used a population-based cohort of normotensive adults in 2010 who were aged 40 years and older at retest in 2015.

RESULTS

Of 676 individuals completing baseline and 5-year follow-up, there were 193 incident cases of hypertension. The overall hypertension incidence rate was 8.374/100 person-years. In multivariable analyses, those who became hypertensive were more likely to be older, have a high waist circumference (incidence rate ratio (IRR): 1.557, 95% CI: 1.074 to 2.259) and be employed (IRR: 1.579, 95% CI: 1.071 to 2.329) at baseline. Being HIV positive and not on antiretroviral therapy at baseline was associated with lower risk of incident hypertension.

CONCLUSIONS

Over a 5-year period, 29% of respondents developed hypertension. Given the high burden of hypertension in South Africa, continued longitudinal follow-up is needed to understand the complex interplay of non-communicable and infectious diseases and their underlying and modifiable risk factors to inform public health prevention strategies and programmes.

Heart failure care and outcomes in a Tanzanian emergency department: A prospective observational study

BACKGROUND

The burden of heart failure is growing in sub-Saharan Africa, but there is a dearth of data characterizing care and outcomes of heart failure patients in the region, particularly in emergency department settings.

METHODS

In a prospective observational study, adult patients presenting with shortness of breath or chest pain to an emergency department in northern Tanzania were consecutively enrolled. Participants with a physician-documented clinical diagnosis of heart failure were included in the present analysis. Standardized questionnaires regarding medical history and medication use were administered at enrollment, and treatments given in the emergency department were recorded. Thirty days after enrollment, a follow-up questionnaire was administered to assess mortality and medication use. Multivariate logistic regression was performed to identify baseline predictors of thirty-day mortality.

RESULTS

Of 1020 enrolled participants enrolled from August 2018 through October 2019, 267 patients (26.2%) were diagnosed with heart failure. Of these, 139 (52.1%) reported a prior history of heart failure, 168 (62.9%) had self-reported history of hypertension, and 186 (69.7%) had NYHA Class III or IV heart failure. At baseline, 40 (15.0%) reported taking a diuretic and 67 (25.1%) reported taking any antihypertensive. Thirty days following presentation, 63 (25.4%) participants diagnosed with heart failure had died. Of 185 surviving participants, 16 (8.6%) reported taking a diuretic, 24 (13.0%) reported taking an antihypertensive, and 26 (14.1%) were rehospitalized. Multivariate predictors of thirty-day mortality included self-reported hypertension (OR = 0.42, 95% CI: 0.21-0.86], p = 0.017) and symptomatic leg swelling at presentation (OR = 2.69, 95% CI: 1.35-5.56, p = 0.006).

CONCLUSION

In a northern Tanzanian emergency department, heart failure is a common clinical diagnosis, but uptake of evidence-based outpatient therapies is poor and thirty-day mortality is high. Interventions are needed to improve care and outcomes for heart failure patients in the emergency department setting.

Burden of out-of-pocket payments among patients with cardiovascular disease in public and private hospitals in Ibadan, South West, Nigeria: a cross-sectional study

OBJECTIVE

Given that the mechanism for financial protection is underdeveloped in Nigeria, out-of-pocket (OOP) payment for treating cardiovascular disease could impose substantial financial burden on individuals and their families. This study estimated the burden of OOP expenditures incurred by a cohort of patients with cardiovascular disease (CVD) in Ibadan, Nigeria.

DESIGN AND SETTINGS

This study used a descriptive cross-sectional study design. A standardised survey questionnaire originally developed by Initiative for Cardiovascular Health Research in Developing Countries was used to electronically collect data from all the 744 patients with CVD who accessed healthcare between 4 November 2019 and 31 January 2020 in the cardiology departments of private and public hospitals in Ibadan, Nigeria. Baseline characteristics of respondents were presented using percentages and proportions. The OOP payments were reported as means±SDs. Costs/OOP payments were in Nigerian Naira (NGN). The average US dollar to NGN at the time of data collection was ₦362.12 per $1. All quantitative data were analysed using STATA V.15.

OUTCOME MEASURES

The burden of outpatient, inpatient and rehabilitative care OOP payments.

RESULTS

Majority of the patients with CVD were within the age range of 45-74 years and 68.55% of them were women. The diagnostic conditions reported among patients with CVD were hypertensive heart failure (84.01%), dilated cardiomyopathy (4.44%), ischaemic heart disease (3.9%) and anaemic heart failure (2.15%). Across all the hospital facilities, the annual direct and indirect outpatient costs were ₦421 595.7±₦855 962.0 ($1164.2±$2363.8) and ₦19 146.5±₦53 610.1 ($52.87±$148.05). Similarly, the average direct and indirect OOP payments per hospitalisation across all facilities were ₦182 302.4±₦249 090.4 ($503.43±$687.87) and ₦14 700.8±₦ 69 297.1 ($40.60±$191.37), respectively. The average rehabilitative cost after discharge from index hospitalisation was ₦30 012.0 ($82.88).

CONCLUSION

The burden of OOP payment among patients with CVD is enormous. There is a need to increase efforts to achieve universal health coverage in Nigeria.

Background and design of a 5-year ST Elevation Myocardial Infarction Cohort in Isfahan, Iran: SEMI-CI study

BACKGROUND

Cardiovascular disease (CVD) is one of the most important causes of mortality and morbidity in Iran. Secondary prevention of acute myocardial infarction (AMI) is necessary. The main aim of this cohort is evaluating clinical, paraclinical, management, and 5-year major events of the participants in Isfahan, Iran.

METHODS

All consecutive patients with AMI hospitalized in Chamran Hospital, Isfahan, during 1 year from march 2015 were recruited and followed for 5 years. ST-Elevation Myocardial Infarction Cohort Study (SEMI-CI) has been initiated as a longitudinal study to evaluate course of patients with AMI in Iran, adherence to evidence-based secondary prevention drug, and five-year events such as death, re-myocardial infarction (REMI), re-hospitalization, congestive heart failure (CHF), and referring to another procedure [percutaneous coronary intervention (PCI), coronary artery bypass graft (CABG), and resynchronization therapy].

RESULTS

A total of 867 patients with ST-elevation myocardial infarction (STEMI) with mean age of 60.91 ± 12.76 years were recruited. 705 (81.3%) subjects were men with mean age of 59.63 ± 12.59 years. 470 (54.2%) patients had anterior AMI (ant-AMI) and the rest had other types of AMI. The ejection fraction (EF) mean was 37.80 ± 11.74 percent. A total of 30 (3.5%) cases of AMI had not received reperfusion. 445 (51.4%) had primary PCI and 392 (45.2%) had thrombolysis at first revascularization strategy. In-hospital death occurred in 72 participants (8.3%). Drug during hospital included: at discharge, 767 (88.5%) received aspirin, 787 (90.7%) statin, 697 (80.4%) beta-blocker, and 480 (55.4%) angiotensin-converting enzyme (ACE) inhibitor.

CONCLUSION

According to the best of our knowledge, it is among few cohorts in Eastern Mediterranean Region (EMR) in patients with AMI. This paper showed methodology of this study in patients with STEMI and its follow-up protocol. We can use this result in policy-making for improving secondary prevention strategies.

Is CD47 a potentially promising therapeutic target in cardiovascular diseases? - Role of CD47 in cardiovascular diseases

CD47 (cluster of differentiation 47) is a ubiquitously expressed transmembrane protein that belongs to the immunoglobulin superfamily. CD47 is both a receptor for the matricellular protein thrombospondin-1 (TSP-1) and a ligand for signal-regulatory protein alpha (SIRPα). Suppression of CD47 activity enhances angiogenesis and blood flow, restores phagocytosis by macrophages, improves ischemic tissue survival, attenuates ischemia reperfusion injury, and reverses atherosclerotic plaque formation. In conclusion, these observations suggest a pathogenic role of CD47 in the development of cardiovascular diseases (CVDs) and indicate that CD47 might be a potentially promising molecular target for treating CVDs. Herein, we highlight the role of CD47 in the CVD pathogenesis and discuss the potential clinical application by targeting CD47 for treating CVDs.

Non-communicable diseases in sub-Saharan Africa: a scoping review of large cohort studies

Background

Non-communicable diseases (NCDs) cause a large and growing burden of morbidity and mortality in sub-Saharan Africa. Prospective cohort studies are key to study multiple risk factors and chronic diseases and are crucial to our understanding of the burden, aetiology and prognosis of NCDs in SSA. We aimed to identify the level of research output on NCDs and their risk factors collected by cohorts in SSA.

Methods

We conducted a scoping review to map the extent of current NCDs research in SSA by identifying studies published after the year 2000 using prospectively collected cohort data on any of the six NCDs (cardiovascular diseases, diabetes, obesity, chronic kidney disease, chronic respiratory diseases, and cancers), ≥1 major risk factor (other than age and sex), set only within SSA, enrolled ≥500 participants, and ≥12 months of follow-up with ≥2 data collection points (or with plans to). We performed a systematic search of databases, a manual search of references lists from included articles and the INDEPTH network website, and study investigators from SSA were contacted for further articles.

Results

We identified 30 cohort studies from the 101 included articles. Eighteen countries distributed in West, Central, East and Southern Africa, were represented. The majority (27%) set in South Africa. There were three studies including children, twenty with adults, and seven with both. 53% of cohorts were sampled in general populations, 47% in clinical populations, and 1 occupational cohort study. Hypertension (n = 23) was most commonly reported, followed by obesity (n = 16), diabetes (n = 15), CKD (n = 6), COPD (n = 2), cervical cancer (n = 3), and breast cancer (n = 1). The majority (n = 22) reported data on at least one demographic/environmental, lifestyle, or physiological risk factor but these data varied greatly.

Conclusions

Most studies collected data on a combination of hypertension, diabetes, and obesity and few studies collected data on respiratory diseases and cancer. Although most collected data on different risk factors the methodologies varied greatly. Several methodological limitations were found including low recruitment rate, low retention rate, and lack of validated and standardized data collection. Our results could guide potential collaborations and maximize impact to improve our global understanding of NCDs (and their risk factors) in SSA and also to inform future research, as well as policies.

Feasibility of a cardiovascular cohort in a Sub-Saharan Africa community: preliminary report of the pilot project TAHES (Tanvè Health Study) in Benin

BACKGROUND

Faced with the growing burden of cardiovascular disease (CVD) including atherosclerotic in Sub-Saharan Africa (SSA), the development of appropriate prediction tools, based on large cohorts, appears useful for prevention.

OBJECTIVE

The objective of the pilot project TAHES (Tanvè Health Study) was to explore the feasibility of a large cohort study focused on CVD and risk factors in Benin.

METHODS

We implemented a prospective cohort over 2 years. The sample consisted of all people aged 25 years or older who had lived for at least the previous 6 months in the villages of Tanvè or Dékanmè. At baseline in February 2015, behaviours and medical histories were recorded using a standardized questionnaire adapted from the WHO Steps instrument; screening questionnaires for angina, claudication, congestive heart failure, and stroke were applied; anthropometric measures and fasting capillary blood glucose were taken. All participants were included in the follow-up phase. Surveillance of target CVD and deaths was implemented through a medical and a community network.

RESULTS

A total of 1,195 participants were enrolled at baseline; women represented 65.5% and the median age was 39 years. The high participation rate (91.4%), the quality of baseline data, and the functionality of the events surveillance network over 8 months indicated good perspective for the feasibility of a large cohort. We recorded a 3.8% prevalence of daily smoking, 3.6% of harmful use of alcohol, 10.7% of obesity, 25.5% of high blood pressure, and 3.5% of diabetes. Prevalence of angina pectoris (2.7%), intermittent claudication (2.0%), congestive heart failure (0.9%), and stroke survival with motor impairment (3‰) were also recorded. Ten deaths occurred during the first 8 months, all within households; a cardiovascular cause was suspected in four cases.

CONCLUSION

These preliminary results support the feasibility of establishing a cohort in Benin. It would require technical and resource support.

The South African Rea Phela Health Study: A randomized controlled trial of communication retention strategies

Epidemiological transitions are occurring throughout Africa. To inform public health programs and policies, longitudinal cohorts investigating non-communicable diseases are needed. However, loss-to-follow up is a major problem. In preparation for a longitudinal study, we conducted a randomized controlled trial to test communication-based retention strategies (message content and delivery methods) among a pilot cohort of South African healthcare workers (n = 1536; median age = 36; women = 1270). Two messaging formats across three delivery modes were tested. Response rates were analyzed by intervention, survey return date and method using chi-square tests and univariate logistic regression. Sixty-seven of 238 (17.4%) control group participants and 238 of 1152 (24.6%) intervention group participants were retained (OR 1.54: CI 1.15–2.07; P = 0.004). Odds of being retained were 1.68 times greater for participants who received regular contact and themed messages compared to control (CI 1.22–2.32; P = 0.001). Neither health status nor clinical condition affected response rates (P>0.05). Time-to-first contact did not impact response rates (P>0.05). Message content and delivery method influenced response rates compared to the control, however no difference was found between intervention groups. Although greater retention is required for valid cohort studies, these findings are the first to quantitatively assess retention factors in Africa.

The association between HIV and atherosclerotic cardiovascular disease in sub-Saharan Africa: a systematic review

Background

Sub-Saharan Africa (SSA) has confronted decades of the HIV epidemic with substantial improvements in access to life-saving antiretroviral therapy (ART). Now, with improved survival, people living with HIV (PLWH) are at increased risk for non-communicable diseases (NCDs), including atherosclerotic cardiovascular disease (CVD). We assessed the existing literature regarding the association of CVD outcomes and HIV in SSA.

Methods

We used the PRISMA guidelines to perform a systematic review of the published literature regarding the association of CVD and HIV in SSA with a focus on CVD surrogate and clinical outcomes in PLWH.

Results

From January 2000 until March 2017, 31 articles were published regarding CVD outcomes among PLWH in SSA. Data from surrogate CVD outcomes (n = 13) suggest an increased risk of CVD events among PLWH in SSA. Although acute coronary syndrome is reported infrequently in SSA among PLWH, limited data from five studies suggest extensive thrombus and hypercoagulability as contributing factors. Additional studies suggest an increased risk of stroke among PLWH (n = 13); however, most data are from immunosuppressed ART-naïve PLWH and thus are potentially confounded by the possibility of central nervous system infections.

Conclusions

Given ongoing gaps in our current understanding of CVD and other NCDs in PLWH in SSA, it is imperative to ascertain the burden of CVD outcomes, and to examine strategies for intervention and best practices to enhance the health of this vulnerable population.

Electronic supplementary material

The online version of this article (10.1186/s12889-017-4940-1) contains supplementary material, which is available to authorized users.

Improving access to HbA1c in sub-Saharan Africa (IA3) cohort: cohort profile

Introduction

Glycated haemoglobin (HbA1c) is the best surrogate of average blood glucose control in diabetic patients, and lowering HbA1c significantly reduces diabetes complications. Moreover, immediate feedback of HbA1c measurement to patients may improve control. However, HbA1c is unavailable in most parts of Africa, a continent with one of the highest burden of diabetes. To translate these evidences, we are conducting a multicentric project in 10 health care facilities in Guinea and Cameroon to evaluate the feasibility and one-year benefit of affordable HbA1c measurement with immediate feedback to patients on diabetes control and related outcomes.

Participants

We consecutively enrolled patients with diabetes mellitus independently of the type of disease. We hypothesised an average 1%-decrease in HbA1c in a 1000-patient study population, with a 20% increase in the number of patients reaching treatment goals within 12 months of intervention and follow-up.

Findings to date

A total of 1, 349 diabetic patients aged 56.2±12.6 years are enrolled (813 in Cameroon and 536 in Guinea) of whom 59.8% are women. The mean duration of diabetes is 7.4±6.3 years and baseline HbA1c is 9.7±2.6% in Guinea and 8.6±2.5% in Cameroon.

Future plans

To investigate whether the introduction of routine HbA1c measurement with immediate feedback to patients and provision of relevant education would improve diabetes control after one year. The impact of the intervention on diabetes associated-complications and mortality warrant further assessment in the long term.

Worldwide Exposures to Cardiovascular Risk Factors and Associated Health Effects: Current Knowledge and Data Gaps

Information on exposure to, and health effects of, cardiovascular disease (CVD) risk factors is needed to develop effective strategies to prevent CVD events and deaths. Here, we provide an overview of the data and evidence on worldwide exposures to CVD risk factors and the associated health effects. Global comparative risk assessment studies have estimated that hundreds of thousands or millions of CVD deaths are attributable to established CVD risk factors (high blood pressure and serum cholesterol, smoking, and high blood glucose), high body mass index, harmful alcohol use, some dietary and environmental exposures, and physical inactivity. The established risk factors plus body mass index are collectively responsible for ≈9.7 million annual CVD deaths, with high blood pressure accounting for more CVD deaths than any other risk factor. Age-standardized CVD death rates attributable to established risk factors plus high body mass index are lowest in high-income countries, followed by Latin America and the Caribbean; they are highest in the region of central and eastern Europe and central Asia. However, estimates of the health effects of CVD risk factors are highly uncertain because there are insufficient population-based data on exposure to most CVD risk factors and because the magnitudes of their effects on CVDs in observational studies are likely to be biased. We identify directions for research and surveillance to better estimate the effects of CVD risk factors and policy options for reducing CVD burden by modifying preventable risk factors.

Determinants of Mean Blood Pressure and Hypertension among Workers in West Africa

Background. This review was undertaken to estimate the mean blood pressure and evaluate its determinants as well as the determinants of hypertension among workers in West Africa. Methods. In a follow-up to an earlier study, a systematic search for articles published between 1980 and August 2015 was undertaken using major databases. Results. A total of 55 articles involving 34,919 different cadres of workers from six countries were retrieved. The mean systolic blood pressure (BP) ranged from 116.6 ± 1.3 mmHg to 151.7 ± 13.6 mmHg while the mean diastolic BP ranged from 69.6 ± 11.0 mmHg to 97.1 ± 9.1 mmHg. Population-wide prehypertension was common. The major determinants of mean BP and hypertension were similar and included male sex, older age group, higher socioeconomic status, obesity, alcohol consumption, plasma glucose, and sodium excretion. Ethnicity and educational level were inconsistently associated with hypertension. Workers at higher risk of cardiovascular event did not perceive themselves as such. Conclusion. The prevailing mean prehypertensive BP, low perception of risk, and clustering of risk factors call for interventions such as healthy diets, improved physical activity, and a favourable work environment. Successful models for improving the cardiovascular health of sedentary informal sector workers in Africa are urgently needed.

Burden of disease in adults admitted to hospital in a rural region of coastal Kenya: an analysis of data from linked clinical and demographic surveillance systems

Background

Estimates of the burden of disease in adults in sub-Saharan Africa largely rely on models of sparse data. We aimed to measure the burden of disease in adults living in a rural area of coastal Kenya with use of linked clinical and demographic surveillance data.

Methods

We used data from 18 712 adults admitted to Kilifi District Hospital (Kilifi, Kenya) between Jan 1, 2007, and Dec 31, 2012, linked to 790 635 person-years of observation within the Kilifi Health and Demographic Surveillance System, to establish the rates and major causes of admission to hospital. These data were also used to model disease-specific disability-adjusted life-years lost in the population. We used geographical mapping software to calculate admission rates stratified by distance from the hospital.

Findings

The main causes of admission to hospital in women living within 5 km of the hospital were infectious and parasitic diseases (303 per 100 000 person-years of observation), pregnancy-related disorders (239 per 100 000 person-years of observation), and circulatory illnesses (105 per 100 000 person-years of observation). Leading causes of hospital admission in men living within 5 km of the hospital were infectious and parasitic diseases (169 per 100 000 person-years of observation), injuries (135 per 100 000 person-years of observation), and digestive system disorders (112 per 100 000 person-years of observation). HIV-related diseases were the leading cause of disability-adjusted life-years lost (2050 per 100 000 person-years of observation), followed by non-communicable diseases (741 per 100 000 person-years of observation). For every 5 km increase in distance from the hospital, all-cause admission rates decreased by 11% (95% CI 7–14) in men and 20% (17–23) in women. The magnitude of this decline was highest for endocrine disorders in women (35%; 95% CI 22–46) and neoplasms in men (30%; 9–45).

Interpretation

Adults in rural Kenya face a combined burden of infectious diseases, pregnancy-related disorders, cardiovascular illnesses, and injuries. Disease burden estimates based on hospital data are affected by distance from the hospital, and the amount of underestimation of disease burden differs by both disease and sex.

Funding

The Wellcome Trust, GAVI Alliance.

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.

Burden of Undiagnosed Hypertension in Sub-Saharan Africa

The burden of hypertension in Sub-Saharan Africa has been increasing over the past few decades. However, a large proportion of the population with hypertension remains undiagnosed, untreated, or inadequately treated, contributing to the rising burden of cardiovascular disease in the region. We conducted a systematic review and meta-analysis to assess the recent burden of hypertension in Sub-Saharan Africa, based on studies published between 2000 and 2013. We pooled data from 33 surveys involving over 110 414 participants of mean age 40 years. Hypertension prevalence varied widely across the studies (range 15%–70%), partly because of differences in participant mean ages (31–76 years). The predicted prevalence of hypertension at mean participant ages of 30, 40, 50, and 60 years were 16%, 26%, 35%, and 44%, respectively, with a pooled prevalence of 30% (95% confidence interval, 27%–34%). Of those with hypertension, only between 7% and 56% (pooled prevalence: 27%; 95% confidence interval, 23%–31%) were aware of their hypertensive status before the surveys. Overall, 18% (95% confidence interval, 14%–22%) of individuals with hypertension were receiving treatment across the studies, and only 7% (95% confidence interval, 5%–8%) had controlled blood pressure. This review found a high prevalence of hypertension, as well as low percentage of hypertension awareness, treatment, and control in Sub-Saharan Africa, highlighting the need for implementation of timely and appropriate strategies for diagnosis, control, and prevention.

HIV-associated renal and genitourinary comorbidities in Africa

With the recent massive scale-up of access to antiretroviral therapy (ART) in resource-limited countries, HIV has become a chronic disease with new challenges. There is mounting evidence of an increased burden of renal and genitourinary diseases among HIV-infected persons caused by direct HIV viral effects and/or indirectly through the development of opportunistic infections, ART medication-related toxicities, and other noncommunicable diseases (NCDs). We review the epidemiology of HIV-associated renal and urogenital diseases, including interactions with kidney-related NCDs such as hypertension, diabetes mellitus, and cardiovascular disease. We also examine the current evidence regarding the impact of HIV infection on the development of urogenital diseases. Highly advisable in sub-Saharan Africa are the establishment of renal disease registries, reviews of existing clinical practice including cost-effectiveness studies, and the adoption and use of HIV-related NCD management, with training for different cadres of health providers. Epidemiological research priorities include prospective studies to evaluate the true prevalence and spectrum of HIV-related renal disease and their progression. Simple diagnostics tools should be evaluated, including urinary dipsticks and point-of-care urea and creatinine tests to screen for kidney injury in primary care settings. Study of urological manifestations of HIV can help determine the extent of disease and outcomes. As patients live longer on ART, the burden of renal and genitourological complications of HIV and of ART can be expected to increase with a commensurate urgency in both discovery and evidence-based improvements in clinical management.

Addressing discrepancies: personal experience of a cardiac mission programme in Africa

The worldwide incidence of cardiovascular disease (CVD) is increasing, reflecting a combination of ongoing infective diseases and a rapid rise in traditional 'western' risk factors. It is estimated that in the next 20 years that CVD be the leading cause of death in developing nations. There are high incidences of rheumatic heart disease, coronary artery disease, cardiomyopathies, uncorrected congenital heart disease and human immunodeficiency virus (HIV) associated disease in many low-income countries. Such high levels combined with a lack of diagnostic tests and therapeutic options means mortality and morbidity rates are high. A number of charities and organizations have tried to address the discrepancy of cardiac care within developing areas although the needs remain great. However there is no one global cardiac organization that coordinates such humanitarian work. The challenges of missionary work include the need for appropriate facilities, financial constraints of clinical consumables, and lack of education of local healthcare staff, making the move away from the mission model difficult. The strategy for delivery of care in developing countries should be long term educational and technical support, so that local case volumes increase. However it must be realized that there are many different levels of local services within developing nations with different health and educational needs, including some countries with very high facilities and skills levels, yet high case loads. This paper highlights the personal experience of our organization and the types of diseases encountered in developing countries.

HIV, tuberculosis, and noncommunicable diseases: what is known about the costs, effects, and cost-effectiveness of integrated care?

Unprecedented investments in health systems in low- and middle-income countries (LMICs) have resulted in more than 8 million individuals on antiretroviral therapy. Such individuals experience dramatically increased survival but are increasingly at risk of developing common noncommunicable diseases (NCDs). Integrating clinical care for HIV, other infectious diseases, and NCDs could make health services more effective and provide greater value. Cost-effectiveness analysis is a method to evaluate the clinical benefits and costs associated with different health care interventions and offers guidance for prioritization of investments and scale-up, especially as resources are increasingly constrained. We first examine tuberculosis and HIV as 1 example of integrated care already successfully implemented in several LMICs; we then review the published literature regarding cervical cancer and depression as 2 examples of NCDs for which integrating care with HIV services could offer excellent value. Direct evidence of the benefits of integrated services generally remains scarce; however, data suggest that improved effectiveness and reduced costs may be attained by integrating additional services with existing HIV clinical care. Further investigation into clinical outcomes and costs of care for NCDs among people living with HIV in LMICs will help to prioritize specific health care services by contributing to an understanding of the affordability and implementation of an integrated approach.

Estimating the prevalence and awareness rates of hypertension in Africa: a systematic analysis

Background

The burden of hypertension is high in Africa, and due to rapid population growth and ageing, the exact burden on the continent is still far from being known. We aimed to estimate the prevalence and awareness rates of hypertension in Africa based on the cut off “≥140/90 mm Hg”.

Methods

We conducted a systematic search of Medline, EMBASE and Global Health. Search date was set from January 1980 to December 2013. We included population-based studies on hypertension, conducted among people aged ≥15 years and providing numerical estimates on the prevalence of hypertension in Africa. Overall pooled prevalence of hypertension in mixed, rural and urban settings in Africa were estimated from reported crude prevalence rates. A meta-regression epidemiological modelling, using United Nations population demographics for the years 1990, 2000, 2010 and 2030, was applied to determine the prevalence rates and number of cases of hypertension in Africa separately for these four years.

Results

Our search returned 7680 publications, 92 of which met the selection criteria. The overall pooled prevalence of hypertension in Africa was 19.7% in 1990, 27.4% in 2000 and 30.8% in 2010, each with a pooled awareness rate (expressed as percentage of hypertensive cases) of 16.9%, 29.2% and 33.7%, respectively. From the modelling, over 54.6 million cases of hypertension were estimated in 1990, 92.3 million cases in 2000, 130.2 million cases in 2010, and a projected increase to 216.8 million cases of hypertension by 2030; each with an age-adjusted prevalence of 19.1% (13.9, 25.5), 24.3% (23.3, 31.6), 25.9% (23.5, 34.0), and 25.3% (24.3, 39.7), respectively.

Conclusion

Our findings suggest the prevalence of hypertension is increasing in Africa, and many hypertensive individuals are not aware of their condition. We hope this research will prompt appropriate policy response towards improving the awareness, control and overall management of hypertension in Africa.

Contemporary aetiology, clinical characteristics and prognosis of adults with heart failure observed in a tertiary hospital in Tanzania: the prospective Tanzania Heart Failure (TaHeF) study

OBJECTIVE

This study aimed to describe the contemporary aetiology, clinical characteristics and mortality and its predictors in heart failure (HF) in Tanzania.

METHODS

Design; Prospective observational study. Setting; Cardiovascular Center of the Muhimbili National Hospital in Dar es Salaam, Tanzania. Patients ≥18 years of age with HF defined by the Framingham criteria.

MAIN OUTCOME MEASURE

All-cause mortality.

RESULTS

Among 427 included patients, 217 (51%) were females and the mean (SD) age was 55 (17) years. HF aetiologies included hypertension (45%), cardiomyopathy (28%), rheumatic heart disease (RHD) (12%) and ischaemic heart disease (9%). Concurrent atrial fibrillation (AF), clinically significant anaemia, diabetes, tuberculosis and HIV were found in 16%, 12%, 12%, 3% and 2%, respectively, while warfarin was used in 3% of the patients. The mortality rate, 22.4 per 100 person-years over a median follow-up of 7 months, was independently associated with AF, HR 3.4 (95% CI 1.6 to 7.0); in-patient 3.2 (1.5 to 6.8); anaemia 2.3 (1.2 to 4.5); pulmonary hypertension 2.1 (1.1 to 4.2) creatinine clearance 0.98 (0.97 to 1.00) and lack of education 2.3 (1.3 to 4.2).

CONCLUSIONS

In HF in Tanzania, patients are younger than in the developed world, but aetiologies are becoming more similar, with hypertension becoming more and RHD less important. Predictors of mortality possible to intervene against are anaemia, AF and lack of education.

Effects of single aortic clamping versus partial aortic clamping techniques on post-operative stroke during coronary artery bypass surgery

BACKGROUND

The aim of this study was to compare the effects of single-clamping and partial-clamping techniques on postoperative stroke during coronary artery bypass surgery.

METHODS

Between December 2008 and December 2012, 2 000 patients who underwent coronary artery bypass grafting in two hospitals were analysed. Post-operative neurological complications were analysed retrospectively in these patients. The cases were divided into two groups: in group 1, 1 500 patients were analysed, in whom proximal anastomosis was performed with partial clamping in a beating heart (n = 1 500, 846 male, 654 female; mean age 63.25 ± 5.72 years; range 43-78 years). In group 2, 500 patients were analysed, in whom proximal anastomosis had been performed by other surgical teams in another hospital, with cross clamping in a resting heart with cardioplegia (n = 500, 296 male, 214 female; mean age 64.83 ± 8.12 years; range 41-81 years). During 30 days post-operatively, neurological deficits, stroke incidence and the relationship of the clinical situation to mortality were analysed.

RESULTS

For both groups, patients were similar in terms of patient characteristics. In group 2, cross-clamp duration and perfusion time were longer; however, time of hospital stay was similar in the two groups. Post-operative stroke was seen in 26 patients in group 1 (1.73%) and in nine in group 2 (1.8%). The difference between the two groups was not statistically significant (p = 0.92). All stroke patients were over the age of 55 years. Seven of the stroke patients died (21.1%). In total, 31 patients died because of multiple organ failure in the postoperative 30 days (group 1: 1.6%; group 2: 1.4%) (p = 0.91). Smoking, diabetes mellitus, hypertension, atrial fibrillation, peripheral vascular disease and hypercholesterolaemia were found to be factors that affected stroke development. Mean duration of hospital stay was 5.1 ± 2.8 days in group 1 and 4.9 ± 3.6 days in group 2 and the difference between the two groups was not statistically significant (p = 0.46).

CONCLUSION

In patients without plaques in the aorta, performing partial clamping did not increase stroke incidence.

New insights on diabetes mellitus and obesity in Africa-part 1: prevalence, pathogenesis and comorbidities

Evidence continues to accumulate on the rising burden of diabetes mellitus at a higher pace in Africa. In a series of two papers, we sought to summarise recent evidence on diabetes and obesity in Africa based on a systematic review of studies published between January 2002 and October 2012. This first paper on the prevalence, pathogenesis and comorbidities shows that the increase in diabetes prevalence has paralleled that of obesity in Africa. Recent surveys on diabetes and obesity have been largely suboptimal. Hence, the need for more representative and robust continent-wide prevalence figures, which may be somehow achieved through pooling of existing data. Prospective studies linking environmental risk factors to disease occurrence and outcomes remain scarce, and genetic factors for diabetes or obesity have not been extensively assessed. The health consequences of diabetes are manifold, and include a complex interaction with other conditions like HIV infection and sickle cell disease/trait.

Recent advances in the epidemiology, outcome, and prevention of myocardial infarction and stroke in sub-Saharan Africa

The early part of the new millennium witnessed reports of a growing burden of cardiovascular disease in Sub-Saharan Africa (SSA). However the contribution of ischemic heart disease and stroke to this increasing burden relative to that caused by hypertensive heart disease, cardiomyopathy and rheumatic heart disease was not clear. Over the last decade, data from the continent has begun to clarify this issue and suggests three main points. The burden of ischemic heart disease relative to other causes of heart disease remains low particularly in the black Africans majority. Stroke caused predominantly by hypertension is now a major cause of disability and premature death. Third, the burden of risk factors for atherosclerosis is increasing rapidly in most urban and some rural regions. A concerted effort to understand the primary drivers of this increase in cardiac risk factors is required to prevent a future epidemic of atherosclerosis and its sequelae.

Metabolic syndrome and fatal outcomes in the post-stroke event: a 5-year cohort study in Cameroon

Background and Purpose

Determinants of post-acute stroke outcomes in Africa have been less investigated. We assessed the association of metabolic syndrome (MetS) and insulin resistance with post-stroke mortality in patients with first-ever-in-lifetime stroke in the capital city of Cameroon (sub-Saharan Africa).

Methods

Patients with an acute first-stroke event (n = 57) were recruited between May and October 2006, and followed for 5 years for mortality outcome. MetS definition was based on the Joint Interim Statement 2009, insulin sensitivity/resistance assessed via glucose-to-insulin ratio, quantitative insulin sensitivity check index and homeostatic model assessment.

Results

Overall, 24 (42%) patients deceased during follow-up. The prevalence of MetS was higher in patients who died after 28 days, 1 year and 5 years from any cause or cardiovascular-related causes (all p≤0.040). MetS was associated with an increased overall mortality both after 1 year (39% vs. 9%) and 5 years of follow-up (55% vs. 26%, p = 0.022). Similarly, fatal events due to cardiovascular-related conditions were more frequent in the presence of MetS both 1 year (37% vs. 9%) and 5 years after the first-ever-in-lifetime stroke (43% vs. 13%, p = 0.017). Unlike biochemical measures of insulin sensitivity and resistance (non-significant), in age- and sex-adjusted Cox models, MetS was associated with hazard ratio (95% CI) of 2.63 (1.03–6.73) and 3.54 (1.00–12.56) respectively for all-cause and cardiovascular mortality 5 years after stroke onset.

Conclusion

The Joint Interim Statement 2009 definition of MetS may aid the identification of a subgroup of black African stroke patients who may benefit from intensification of risk factor management.

Coronary artery disease in Africa and the Middle East

Countries in Africa and the Middle East bear a heavy burden from cardiovascular disease. The prevalence of coronary heart disease is promoted in turn by a high prevalence of cardiovascular risk factors, particularly smoking, hypertension, dyslipidemia, diabetes, and sedentary lifestyles. Patients in Africa and the Middle East present with myocardial infarction at a younger age, on average, compared with patients elsewhere. The projected future burden of mortality from coronary heart disease in Africa and the Middle East is set to outstrip that observed in other geographical regions. Recent detailed nationally representative epidemiological data are lacking for many countries, and high proportions of transient expatriate workers in countries such as Saudi Arabia and the United Arab Emirates complicate the construction of such datasets. However, the development of national registries in some countries is beginning to reveal the nature of coronary heart disease. Improving lifestyles (reducing calorie intake and increasing physical activity) in patients in the region will be essential, although cultural and environmental barriers will render this difficult. Appropriate prescribing of pharmacologic treatments is essential in the prevention and management of cardiovascular disease. In particular, recent controversies relating to the therapeutic profile of beta-blockers may have reduced their use. The current evidence base suggests that beta-blockers are as effective as other therapies in preventing cardiovascular disease and that concerns relating to their use in hypertension and cardiovascular disease have been overstated.