Health trends, inequalities and opportunities in South Africa's provinces, 1990-2019: findings from the Global Burden of Disease 2019 Study

BACKGROUND

Over the last 30 years, South Africa has experienced four 'colliding epidemics' of HIV and tuberculosis, chronic illness and mental health, injury and violence, and maternal, neonatal, and child mortality, which have had substantial effects on health and well-being. Using data from the 2019 Global Burden of Diseases, Injuries and Risk Factors Study (GBD 2019), we evaluated national and provincial health trends and progress towards important Sustainable Development Goal targets from 1990 to 2019.

METHODS

We analysed GBD 2019 estimates of mortality, non-fatal health loss, summary health measures and risk factor burden, comparing trends over 1990-2007 and 2007-2019. Additionally, we decomposed changes in life expectancy by cause of death and assessed healthcare system performance.

RESULTS

Across the nine provinces, inequalities in mortality and life expectancy increased over 1990-2007, largely due to differences in HIV/AIDS, then decreased over 2007-2019. Demographic change and increases in non-communicable diseases nearly doubled the number of years lived with disability between 1990 and 2019. From 1990 to 2019, risk factor burdens generally shifted from communicable and nutritional disease risks to non-communicable disease and injury risks; unsafe sex remained the top risk factor. Despite widespread improvements in healthcare system performance, the greatest gains were generally in economically advantaged provinces.

CONCLUSIONS

Reductions in HIV/AIDS and related conditions have led to improved health since 2007, though most provinces still lag in key areas. To achieve health targets, provincial governments should enhance health investments and exchange of knowledge, resources and best practices alongside populations that have been left behind, especially following the COVID-19 pandemic.

Rationale and design of the African Cardiomyopathy and Myocarditis Registry Program: The IMHOTEP study

BACKGROUND

Heart failure (HF), the dominant form of cardiovascular disease in Africans, is mainly due to hypertension, rheumatic heart disease and cardiomyopathy. Cardiomyopathies pose a great challenge because of poor prognosis and high prevalence in low- and middle-income countries (LMICs). Little is known about the etiology and outcome of cardiomyopathy in Africa. Specifically, the role of myocarditis and the genetic causes of cardiomyopathy are largely unidentified in Africans.

METHOD

The African Cardiomyopathy and Myocarditis Registry Program (the IMHOTEP study) is a pan-African multi-centre, hospital-based cohort study, designed with the primary aim of describing the clinical characteristics, genetic causes, prevalence, management and outcome of cardiomyopathy and myocarditis in children and adults. The secondary aim is to identify barriers to the implementation of evidence-based care and provide a platform for trials and other intervention studies to reduce morbidity and mortality in cardiomyopathy. The registry consists of a prospective cohort of newly diagnosed (i.e., incident) cases and a retrospective (i.e., prevalent) cohort of existing cases from participating centres. Patients with cardiomyopathy and myocarditis will be subjected to a standardized 3-stage diagnostic process. To date, 750 patients have been recruited into the multi-centre pilot phase of the study.

CONCLUSION

The IMHOTEP study will provide comprehensive and novel data on clinical features, genetic causes, prevalence and outcome of African children and adults with all forms of cardiomyopathy and myocarditis in Africa. Based on these findings, appropriate strategies for management and prevention of the cardiomyopathies in LMICs are likely to emerge.

Cadherin 2-Related Arrhythmogenic Cardiomyopathy: Prevalence and Clinical Features

BACKGROUND

Arrhythmogenic cardiomyopathy (ACM) is an inherited cardiac disease characterized by fibrofatty replacement of the right and left ventricle, often causing ventricular dysfunction and life-threatening arrhythmias. Variants in desmosomal genes account for up to 60% of cases. Our objective was to establish the prevalence and clinical features of ACM stemming from pathogenic variants in the nondesmosomal cadherin 2 (CDH2), a novel genetic substrate of ACM.

METHODS

A cohort of 500 unrelated patients with a definite diagnosis of ACM and no disease-causing variants in the main ACM genes was assembled. Genetic screening of CDH2 was performed through next-generation or Sanger sequencing. Whenever possible, cascade screening was initiated in the families of CDH2-positive probands, and clinical evaluation was performed.

RESULTS

Genetic screening of CDH2 led to the identification of 7 rare variants: 5, identified in 6 probands, were classified as pathogenic or likely pathogenic. The previously established p.D407N pathogenic variant was detected in 2 additional probands. Probands and family members with pathogenic/likely pathogenic variants in CDH2 were clinically evaluated, and along with previously published cases, altogether contributed to the identification of gene-specific features (13 cases from this cohort and 11 previously published, for a total of 9 probands and 15 family members). Ventricular arrhythmic events occurred in most CDH2-positive subjects (20/24, 83%), while the occurrence of heart failure was rare (2/24, 8.3%). Among probands, sustained ventricular tachycardia and sudden cardiac death occurred in 5/9 (56%).

CONCLUSIONS

In this worldwide cohort of previously genotype-negative ACM patients, the prevalence of probands with CDH2 pathogenic/likely pathogenic variants was 1.2% (6/500). Our data show that this cohort of CDH2-ACM patients has a high incidence of ventricular arrhythmias, while evolution toward heart failure is rare.

Exploring how a genetic attribution to disease relates to stigma experiences of Xhosa patients with schizophrenia in South Africa

BACKGROUND

Over the past three decades, a range of international stakeholders have highlighted the possibility that genomic research may impact stigma associated with psychiatric disorders. Limited research has been conducted in Africa to investigate this relation.

METHOD

In the present study, using focus group discussions, we explored the relation between genetic attribution and stigma among 36 Xhosa people with schizophrenia. We addressed three main questions: (1) What causal beliefs do Xhosa people with schizophrenia use to explain their illness and to what extent do genetic explanations play a role in these beliefs? (2) What are the internalised stigma experiences of Xhosa people with schizophrenia? (3) How do genetic explanations relate to stigma experiences, if at all?

RESULTS

Most participants were able to define genetics and some linked genetics to disease causation. Despite adequate knowledge of genetics and an emphasis on genetic explanations of schizophrenia in the study, most participants held a multitude of causal explanations including: psychosocial, environmental, and cultural. Moreover, participants rarely mentioned disease cause when describing their stigma experiences.

DISCUSSION

For this population group, there was no straight-forward relation between a genetic attribution and stigma. Therefore, we did not find evidence that genetic attribution may significantly increase stigma. Although North American and European literature provides conflicting evidence regarding this relation, there is increased consensus that biomedical explanations for psychiatric disorders may reduce blame. This study found evidence supporting that consensus. This study provides an empirical foundation to inform ongoing work on the psychosocial implications of psychiatric genomics research in non-Western contexts.

N-terminal pro BNP and galectin-3 are prognostic biomarkers of acute heart failure in sub-Saharan Africa: lessons from the BAHEF trial

Aims

The relationship between N‐terminal pro‐brain natriuretic peptide (NT‐pro‐BNP) and galectin‐3 and outcomes has not been studied in African patients with acute heart failure (AHF). The current analysis sought to describe the association between plasma levels of NT‐pro‐BNP and galectin‐3 and cardiovascular (CV) death or heart failure (HF) hospitalization, as well as their associations with symptoms and echocardiography markers of left and right ventricular remodelling among AHF patientsv in sub‐Saharan Africa.

Methods and results

In a subset of 80 patients with complete data in a study assessing the effects of hydralazine and nitrates in patients with AHF (BAHEF trial; NCT01822808), NT‐pro‐BNP and galectin‐3 analyses were performed, and the association with various characteristics and outcome measures assessed. The mean age of the patients for whom the aforementioned biomarkers were measured was 52.6 years, with 52.5% women. Galectin‐3 at baseline predicted changes (Week 24 to baseline) in left ventricular ejection fraction, left ventricular end‐systolic diameter, left ventricular end‐diastolic diameter, and tricuspid annular plane systolic excursion. Biomarkers and their changes were not associated with changes in 6 min walk test at 24 weeks. Baseline galectin‐3 and change in NT‐pro‐BNP were associated with improvements in dyspnoea at 24 weeks. Nine patients had an HF readmission or died of CV causes through 24 weeks (11.6%). Both biomarkers at baseline predicted combined CV death or HF hospitalization through Week 24 (P‐values = 0.0328 and 0.0001, respectively).

Conclusions

In a cohort of patients with AHF from sub‐Saharan Africa, NT‐pro‐BNP and galectin‐3 at baseline and their changes were associated with some changes in dyspnoea, echocardiographic remodelling, and CV death or HF hospitalization through Week 24. These tests have potential of being used for risk stratification of AHF patients in sub‐Saharan Africa where resources are scarce.

The INVICTUS rheumatic heart disease research program: Rationale, design and baseline characteristics of a randomized trial of rivaroxaban compared to vitamin K antagonists in rheumatic valvular disease and atrial fibrillation

BACKGROUND

Rheumatic heart disease (RHD) is a neglected disease affecting 33 million people, mainly in low and middle income countries. Yet very few large trials or registries have been conducted in this population. The INVICTUS program of research in RHD consists of a randomized-controlled trial (RCT) of 4500 patients comparing rivaroxaban with vitamin K antagonists (VKA) in patients with RHD and atrial fibrillation (AF), a registry of 17,000 patients to document the contemporary clinical course of patients with RHD, including a focused sub-study on pregnant women with RHD within the registry. This paper describes the rationale, design, organization and baseline characteristics of the RCT and a summary of the design of the registry and its sub-study. Patients with RHD and AF are considered to be at high risk of embolic strokes, and oral anticoagulation with VKAs is recommended for stroke prevention. But the quality of anticoagulation with VKA is poor in developing countries. A drug which does not require monitoring, and which is safe and effective for preventing stroke in patients with valvular AF, would fulfill a major unmet need.

METHODS

The INVestIgation of rheumatiC AF Treatment Using VKAs, rivaroxaban or aspirin Studies (INVICTUS-VKA) trial is an international, multicentre, randomized, open-label, parallel group trial, testing whether rivaroxaban 20 mg given once daily is non-inferior (or superior) to VKA in patients with RHD, AF, and an elevated risk of stroke (mitral stenosis with valve area ≤2 cm2, left atrial spontaneous echo-contrast or thrombus, or a CHA2DS2VASc score ≥2). The primary efficacy outcome is a composite of stroke or systemic embolism and the primary safety outcome is the occurrence of major bleeding. The trial has enrolled 4565 patients from 138 sites in 23 countries from Africa, Asia and South America. The Registry plans to enroll an additional 17,000 patients with RHD and document their treatments, and their clinical course for at least 2 years. The pregnancy sub-study will document the clinical course of pregnant women with RHD.

CONCLUSION

INVICTUS is the largest program of clinical research focused on a neglected cardiovascular disease and will provide new information on the clinical course of patients with RHD, and approaches to anticoagulation in those with concomitant AF.

Burden of non-communicable diseases in sub-Saharan Africa, 1990-2017: results from the Global Burden of Disease Study 2017

BACKGROUND

Although the burden of disease in sub-Saharan Africa continues to be dominated by infectious diseases, countries in this region are undergoing a demographic transition leading to increasing prevalence of non-communicable diseases (NCDs). To inform health system responses to these changing patterns of disease, we aimed to assess changes in the burden of NCDs in sub-Saharan Africa from 1990 to 2017.

METHODS

We used data from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2017 to analyse the burden of NCDs in sub-Saharan Africa in terms of disability-adjusted life-years (DALYs)-with crude counts as well as all-age and age-standardised rates per 100 000 population-with 95% uncertainty intervals (UIs). We examined changes in burden between 1990 and 2017, and differences across age, sex, and regions. We also compared the observed NCD burden across countries with the expected values based on a country's Socio-demographic Index.

FINDINGS

All-age total DALYs due to NCDs increased by 67·0% between 1990 (90·6 million [95% UI 81·0-101·9]) and 2017 (151·3 million [133·4-171·8]), reflecting an increase in the proportion of total DALYs attributable to NCDs (from 18·6% [95% UI 17·1-20·4] to 29·8% [27·6-32·0] of the total burden). Although most of this increase can be explained by population growth and ageing, the age-standardised DALY rate (per 100 000 population) due to NCDs in 2017 (21 757·7 DALYs [95% UI 19 377·1-24 380·7]) was almost equivalent to that of communicable, maternal, neonatal, and nutritional diseases (26 491·6 DALYs [25 165·2-28 129·8]). Cardiovascular diseases were the second leading cause of NCD burden in 2017, resulting in 22·9 million (21·5-24·3) DALYs (15·1% of the total NCD burden), after the group of disorders categorised as other NCDs (28·8 million [25·1-33·0] DALYs, 19·1%). These categories were followed by neoplasms, mental disorders, and digestive diseases. Although crude DALY rates for all NCDs have decreased slightly across sub-Saharan Africa, age-standardised rates are on the rise in some countries (particularly those in southern sub-Saharan Africa) and for some NCDs (such as diabetes and some cancers, including breast and prostate cancer).

INTERPRETATION

NCDs in sub-Saharan Africa are posing an increasing challenge for health systems, which have to date largely focused on tackling infectious diseases and maternal, neonatal, and child deaths. To effectively address these changing needs, countries in sub-Saharan Africa require detailed epidemiological data on NCDs.

FUNDING

Bill & Melinda Gates Foundation, National Health and Medical Research Centre (Australia).

Regional Patterns and Association Between Obesity and Hypertension in Africa: Evidence From the H3Africa CHAIR Study

Hypertension and obesity are the most important modifiable risk factors for cardiovascular diseases, but their association is not well characterized in Africa. We investigated regional patterns and association of obesity with hypertension among 30 044 continental Africans. We harmonized data on hypertension (defined as previous diagnosis/use of antihypertensive drugs or blood pressure [BP]≥140/90 mmHg/BP≥130/80 mmHg) and obesity from 30 044 individuals in the Cardiovascular H3Africa Innovation Resource across 13 African countries. We analyzed data from population-based controls and the Entire Harmonized Dataset. Age-adjusted and crude proportions of hypertension were compared regionally, across sex, and between hypertension definitions. Logit generalized estimating equation was used to determine the independent association of obesity with hypertension (P value <5%). Participants were 56% women; with mean age 48.5±12.0 years. Crude proportions of hypertension (at BP≥140/90 mmHg) were 47.9% (95% CI, 47.4-48.5) for Entire Harmonized Dataset and 42.0% (41.1-42.7) for population-based controls and were significantly higher for the 130/80 mm Hg threshold at 59.3% (58.7-59.9) in population-based controls. The age-adjusted proportion of hypertension at BP≥140/90 mmHg was the highest among men (33.8% [32.1-35.6]), in western Africa (34.7% [33.3-36.2]), and in obese individuals (43.6%; 40.3-47.2). Obesity was independently associated with hypertension in population-based controls (adjusted odds ratio, 2.5 [2.3-2.7]) and odds of hypertension in obesity increased with increasing age from 2.0 (1.7-2.3) in younger age to 8.8 (7.4-10.3) in older age. Hypertension is common across multiple countries in Africa with 11.9% to 51.7% having BP≥140/90 mmHg and 39.5% to 69.4% with BP≥130/80 mmHg. Obese Africans were more than twice as likely to be hypertensive and the odds increased with increasing age.

Prevalence of group A Streptococcal infection in Africa to inform GAS vaccines for rheumatic heart disease: A systematic review and meta-analysis

BACKGROUND

The prevalence of group A streptococcal (GAS) disease is estimated at >18.1 million cases with an incidence of >1.78 million cases per year. While a significant cause of mortality and morbidity on the global scale, the burden of GAS disease in Africa is unknown. We conducted a systematic review on the prevalence of GAS disease among children and adults in Africa and the frequency and distribution of emm types among isolates.

METHODS

We performed a comprehensive literature search in a number of databases, using an African search filter. Two reviewers independently selected articles meeting pre-specified criteria and extracted relevant data as per a data extraction form. We applied the random-effects meta-analysis model to aggregate GAS prevalence estimates with 95% CI for GAS prevalence, incorporating the Freeman-Tukey transformation to account for between-study variability.

RESULTS

Twenty-five studies were included. Invasive GAS disease prevalence ranged from 0.6% to 10.8% in samples from normally-sterile sites including blood, CSF and soft tissue. A single study reported a prevalence of 74% in skin infections. Prevalence of emm types varied with up to 88 different strains reported, corresponding to a vaccine coverage of 28% to 65%. The pooled prevalence of GAS in persons presenting with pharyngitis was 21% (95% CI, 17% to 26%).

CONCLUSIONS

The prevalence of GAS remains high among symptomatic individuals residing in Africa. Data on molecular strain characterisation of GAS in Africa is largely non-existent, thus the need for further studies is warranted to inform current prevention efforts including vaccine development.

Prevalence and progression of rheumatic heart disease: a global systematic review and meta-analysis of population-based echocardiographic studies

This systematic review and meta-analysis aimed to provide a contemporaneous estimate of the global burden of rheumatic heart disease (RHD) from echocardiographic population-based studies. We searched multiple databases between January 01, 1996 and October 17, 2017. Random-effect meta-analysis was used to pool data. We included 82 studies (1,090,792 participant) reporting data on the prevalence of RHD and 9 studies on the evolution of RHD lesions. The pooled prevalence of RHD was 26.1‰ (95%CI 19.2–33.1) and 11.3‰ (95%CI 7.2–16.2) for studies which used the World Heart Federation (WHF) and World Health Organization (WHO) criteria, respectively. The prevalence of RHD varied inversely with the level of a country’s income, was lower with the WHO criteria compared to the WHF criteria, and was lowest in South East Asia. Definite RHD progressed in 7.5% (95% CI 1.5–17.6) of the cases, while 60.7% (95% CI 42.4–77.5) of cases remained stable over the course of follow-up. The proportion of cases borderline RHD who progressed to definite RHD was 11.3% (95% CI 6.9–16.5). The prevalence of RHD across WHO regions remains high. The highest prevalence of RHD was noted among studies which used the WHF diagnostic criteria. Definite RHD tends to progress or remain stable over time.

Marked variation in heritability estimates of left ventricular mass depending on modality of measurement

Left ventricular (LV) hypertrophy is a strong risk factor for heart failure and cardiovascular death. ECG measures of LV mass are estimated as heritable in twin and family-based analyses and heritability estimates of LV mass measured by echocardiography are lower. We hypothesised that CMR-derived measurements, being more precise than echocardiographic measurements, would advance our understanding of heritable LV traits. We phenotyped 116 British families (427 individuals) by CMR and ECG, and undertook heritability analyses using variance-components (QTDT) and GWAS SNP-based (GCTA-GREML) methods. ECG-based traits such as LV mass and Sokolow-Lyon duration showed substantial estimates of heritability (60%), whereas CMR-derived LV mass was only modestly heritable (20%). However, the ECG LV mass was positively correlated with the lateral diameter of the chest (rho = 0.67), and adjustment for this attenuated the heritability estimate (42%). Finally, CMR-derived right ventricular mass showed considerable heritability (44%). Heritability estimates of LV phenotypes show substantial variation depending on the modality of measurement, being greater when measured by ECG than CMR. This may reflect the differences between electrophysiological as opposed to anatomical hypertrophy. However, ECG LV hypertrophy traits are likely to be influenced by genetic association with anthropometric measures, inflating their overall measured heritability.

Statistics on the use of cardiac electronic devices and interventional electrophysiological procedures in Africa from 2011 to 2016: report of the Pan African Society of Cardiology (PASCAR) Cardiac Arrhythmias and Pacing Task Forces

Aims

To provide comprehensive information on the access and use of cardiac implantable electronic devices (CIED) and catheter ablation procedures in Africa.

Methods and results

The Pan-African Society of Cardiology (PASCAR) collected data on invasive management of cardiac arrhythmias from 2011 to 2016 from 31 African countries. A specific template was completed by physicians, and additional information obtained from industry. Information on health care systems, demographics, economics, procedure rates, and specific training programs was collected. Considerable heterogeneity in the access to arrhythmia care was observed across Africa. Eight of the 31 countries surveyed (26%) did not perform pacemaker implantations. The median pacemaker implantation rate was 2.66 per million population per country (range: 0.14–233 per million population). Implantable cardioverter-defibrillator and cardiac resynchronization therapy were performed in 12/31 (39%) and 15/31 (48%) countries respectively, mostly by visiting teams. Electrophysiological studies, including complex catheter ablations were performed in all countries from Maghreb, but only one sub-Saharan African country (South Africa). Marked variation in cost (up to 1000-fold) was observed across countries with an inverse correlation between implant rates and the procedure fees standardized to the gross domestic product per capita. Lack of economic resources and facilities, high cost of procedures, deficiency of trained physicians, and non-existent fellowship programs were the main drivers of under-utilization of interventional cardiac arrhythmia care.

Conclusion

There is limited access to CIED and ablation procedures in Africa. A quarter of countries did not have pacemaker implantation services, and catheter ablations were only available in one country in sub-Saharan Africa.

Use of broad consent and related procedures in genomics research: Perspectives from research participants in the Genetics of Rheumatic Heart Disease (RHDGen) study in a University Teaching Hospital in Zambia

The use of broad consent for genomics research raises important ethical questions for the conduct of genomics research, including relating to its acceptability to research participants and comprehension of difficult scientific concepts. To explore these and other challenges, we conducted a study using qualitative methods with participants enrolled in an H3Africa Rheumatic Heart Disease genomics study (the RHDGen network) in Zambia to explore their views on broad consent, sample and data sharing and secondary use. In-depth interviews were conducted with RHDGen participants (n = 18), study staff (n = 5) and with individuals who refused to participate (n = 3). In general, broad consent was seen to be reasonable if reasons for storing the samples for future research use were disclosed. Some felt that broad consent should be restricted by specifying planned future studies and that secondary research should ideally relate to original disease for which samples were collected. A few participants felt that broad consent would delay the return of research results to participants. This study echoes findings in other similar studies in other parts of the continent that suggested that broad consent could be an acceptable consent model in Africa if careful thought is given to restrictions on re-use.

Status of cardiac arrhythmia services in Africa in 2018: a PASCAR Sudden Cardiac Death Task Force report

Background

There is limited information on the availability of health services to treat cardiac arrhythmias in Africa.

Methods

The Pan–African Society of Cardiology (PASCAR) Sudden Cardiac Death Task Force conducted a survey of the burden of cardiac arrhythmias and related services over two months (15 October to 15 December) in 2017. An electronic questionnaire was completed by general cardiologists and electrophysiologists working in African countries. The questionnaire focused on availability of human resources, diagnostic tools and treatment modalities in each country.

Results

We received responses from physicians in 33 out of 55 (60%) African countries. Limited use of basic cardiovascular drugs such as anti–arrhythmics and anticoagulants prevails. Non–vitamin K–dependent oral anticoagulants (NOACs) are not widely used on the continent, even in North Africa. Six (18%) of the sub–Saharan African (SSA) countries do not have a registered cardiologist and about one–third do not have pacemaker services. The median pacemaker implantation rate was 2.66 per million population per country, which is 200–fold lower than in Europe. The density of pacemaker facilities and operators in Africa is quite low, with a median of 0.14 (0.03–6.36) centres and 0.10 (0.05–9.49) operators per million population. Less than half of the African countries have a functional catheter laboratory with only South Africa providing the full complement of services for cardiac arrhythmia in SSA. Overall, countries in North Africa have better coverage, leaving more than 110 million people in SSA without access to effective basic treatment for cardiac conduction disturbances.

Conclusion

The lack of diagnostic and treatment services for cardiac arrhythmias is a common scenario in the majority of SSA countries, resulting in sub–optimal care and a subsequent high burden of premature cardiac death. There is a need to improve the standard of care by providing essential services such as cardiac pacemaker implantation.

ANIMA: Association network integration for multiscale analysis

Contextual functional interpretation of -omics data derived from clinical samples is a classical and difficult problem in computational systems biology. The measurement of thousands of data points on single samples has become routine but relating ‘big data’ datasets to the complexities of human pathobiology is an area of ongoing research. Complicating this is the fact that many publicly available datasets use bulk transcriptomics data from complex tissues like blood. The most prevalent analytic approaches derive molecular ‘signatures’ of disease states or apply modular analysis frameworks to the data. Here we describe ANIMA (association network integration for multiscale analysis), a network-based data integration method using clinical phenotype and microarray data as inputs. ANIMA is implemented in R and Neo4j and runs in Docker containers. In short, the build algorithm iterates over one or more transcriptomics datasets to generate a large, multipartite association network by executing multiple independent analytic steps (differential expression, deconvolution, modular analysis based on co-expression, pathway analysis) and integrating the results. Once the network is built, it can be queried directly using Cypher (a graph query language), or by custom functions that communicate with the graph database via language-specific APIs. We developed a web application using Shiny, which provides fully interactive, multiscale views of the data. Using our approach, we show that we can reconstruct multiple features of disease states at various scales of organization, from transcript abundance patterns of individual genes through co-expression patterns of groups of genes to patterns of cellular behaviour in whole blood samples, both in single experiments as well in meta-analyses of multiple datasets.

Clinical characteristics and outcome of lone atrial fibrillation at a tertiary referral centre: the Groote Schuur Hospital experience

INTRODUCTION

Atrial fibrillation (AF) is a relatively common arrhythmia. When AF represents an electrophysiological phenomenon in structurally normal hearts, it is termed lone AF. This study was a retrospective, case-based analysis of patients attending the Cardiac Clinic at Groote Schuur Hospital (GSH) and describes the clinical characteristics and outcomes of patients classified as having lone atrial fibrillation. To the best of our knowledge there are no such studies reported from Africa.

METHODS

This was a retrospective, descriptive study in which 289 medical records of patients with AF at the GSH Cardiac Clinic were reviewed from 1992 to 2006. The clinical data were interrogated to exclude identifiable causes of AF. Information on clinical characteristics and outcomes were entered into a data-entry form. Baseline descriptive statistics were expressed as means and range for continuous variables, and counts with percentages for categorical variables.

RESULTS

Fifteen per cent (n = 42) of patients were identified as having lone AF, with a mean follow-up time of 5.8 years. Males comprised 57% (n = 24) and females 43% (n = 18). Fifty per cent (n = 21) of the patients had paroxysmal AF, 29% (n = 12) had persistent AF, and 12% (n = 5) progressed from paroxysmal to permanent AF. Subsets of lone AF included concomitant atrial flutter (17%) (n = 7) and sick sinus syndrome (21%) (n = 9). Complications were stroke (10%) (n = 4), tachycardia-related cardiomyopathy (17%) (n = 7) and bleeding complications on warfarin (11%) (n = 3).

CONCLUSIONS

Lone AF is not an uncommon arrhythmia, with a preponderance in thin, middle-aged males. The symptoms of lone AF can be debilitating. It has associated morbidity, including tachycardia-related cardiomyopathy and thromboembolism. Rate control and appropriate anticoagulation are the cornerstones of patient management.

Established and novel pathophysiological mechanisms of pericardial injury and constrictive pericarditis

This review article aims to: (1) discern from the literature the immune and inflammatory processes occurring in the pericardium following injury; and (2) to delve into the molecular mechanisms which may play a role in the progression to constrictive pericarditis. Pericarditis arises as a result of a wide spectrum of pathologies of both infectious and non-infectious aetiology, which lead to various degrees of fibrogenesis. Current understanding of the sequence of molecular events leading to pathological manifestations of constrictive pericarditis is poor. The identification of key mechanisms and pathways common to most fibrotic events in the pericardium can aid in the design and development of novel interventions for the prevention and management of constriction. We have identified through this review various cellular events and signalling cascades which are likely to contribute to the pathological fibrotic phenotype. An initial classical pattern of inflammation arises as a result of insult to the pericardium and can exacerbate into an exaggerated or prolonged inflammatory state. Whilst the implication of major drivers of inflammation and fibrosis such as tumour necrosis factor and transforming growth factor β were foreseeable, the identification of pericardial deregulation of other mediators (basic fibroblast growth factor, galectin-3 and the tetrapeptide Ac-SDKP) provides important avenues for further research.

Digoxin and clinical outcomes in the Global Rheumatic Heart Disease Registry

OBJECTIVE

Digoxin is widely used in patients with rheumatic heart disease (RHD) despite a lack of data on its impact on clinical outcomes. We aimed to determine the association of digoxin use on clinical outcomes in patients with RHD.

METHODS

We performed a retrospective analysis of the association of digoxin use with mortality at 2 years in a large RHD registry. Secondary outcomes were recurrent heart failure (HF) and hospitalisation for any cause. We assessed associations using multivariable logistic regression in the entire cohort and in subgroups of patients with atrial fibrillation (AF) and HF. We also estimated average treatment effects from propensity-adjusted analyses using inverse probability treatment weighting.

RESULTS

Information on digoxin use at baseline was available for 98.7% (3298/3343) of patients. In the overall population, digoxin was significantly associated with mortality (OR 1.63, 95% CI 1.30 to 2.04, p<0.0001) and recurrent HF (OR 1.48, 95% CI 1.07 to 2.04, p=0.019). On propensity-weighted analyses, this effect was markedly attenuated (OR 1.05, 95% CI 1.01 to 1.09, p=0.005). Patients in sinus rhythm without HF had a higher propensity-adjusted odds of death with digoxin use (OR 1.06, 95% CI 1.01 to 1.12, p=0.015), but those with both AF and HF had lower mortality (OR 0.88, 95% CI 0.80 to 0.98, p=0.019).

CONCLUSION

Digoxin use is associated with higher mortality in patients with RHD, but this is greatly attenuated on propensity adjustment, indicating the presence of substantial treatment bias. The adjusted estimates may therefore not be reliable, and large randomised trials are needed to determine the true effect of digoxin in patients with RHD.

The Cape Town Declaration on Access to Cardiac Surgery in the Developing World

Mission

to urge all relevant entities within the international cardiac surgery, industry and government sectors to commit to develop and implement an effective strategy to address the scourge of rheumatic heart disease in the developing world through increased access to life-saving cardiac surgery.

Rationale and design of the comparison of 3 combination therapies in lowering blood pressure in black Africans (CREOLE study): 2 × 3 factorial randomized single-blind multicenter trial

BACKGROUND

Current hypertension guidelines recommend the use of combination therapy as first-line treatment or early in the management of hypertensive patients. Although there are many possible combinations of blood pressure(BP)-lowering therapies, the best combination for the black population is still a subject of debate because no large randomized controlled trials have been conducted in this group to compare the efficacy of different combination therapies to address this issue.

METHODS

The comparison of 3 combination therapies in lowering BP in the black Africans (CREOLE) study is a randomized single-blind trial that will compare the efficacy of amlodipine plus hydrochlorothiazide versus amlodipine plus perindopril and versus perindopril plus hydrochlorothiazide in blacks residing in sub-Saharan Africa (SSA). Seven hundred two patients aged 30-79 years with a sitting systolic BP of 140 mm Hg and above, and less than 160 mm Hg on antihypertensive monotherapy, or sitting systolic BP of 150 mm Hg and above, and less than 180 mm Hg on no treatment, will be centrally randomized into any of the 3 arms (234 into each arm). The CREOLE study is taking place in 10 sites in SSA, and the primary outcome measure is change in ambulatory systolic BP from baseline to 6 months. The first patient was randomized in June 2017, and the trial will be concluded by 2019.

CONCLUSIONS

The CREOLE trial will provide unique information as to the most efficacious 2-drug combination in blacks residing in SSA and thereby inform the development of clinical guidelines for the treatment of hypertension in this subregion.

Prevalence of rheumatic heart disease in Zambian school children

BACKGROUND

The large global burden of rheumatic heart disease (RHD) has come to light in recent years following robust epidemiologic studies. As an operational research component of a broad program aimed at primary and secondary prevention of RHD, we sought to determine the current prevalence of RHD in the country's capital, Lusaka, using a modern imaging-based screening methodology. In addition, we wished to evaluate the practicality of training local radiographers in echocardiography screening methods.

METHODS

Echocardiography was conducted on a random sample of students in 15 schools utilizing a previously validated, abbreviated screening protocol. Through a task-shifting scheme, and in the spirit of capacity-building to enhance local diagnostic and research skills, general radiographers based at Lusaka University Teaching Hospital (UTH) were newly trained to use portable echocardiography devices. Students deemed as screen-positive were referred for comprehensive echocardiography and clinical examination at UTH. Cardiac abnormalities were classified according to standard World Heart Federation criteria.

RESULTS

Of 1102 students that were consented and screened, 53 students were referred for confirmatory echocardiography. Three students had definite RHD, 10 had borderline RHD, 29 were normal, and 11 students were lost to follow-up. The rates of definite, borderline, and total RHD were 2.7 per 1000, 9.1 per 1000, and 11.8 per 1000, respectively. Anterior mitral valve leaflet thickening and chordal thickening were the most common morphological defects. The pairwise kappa test showed fair agreement between the local radiographers and an echocardiographer quality assurance specialist.

CONCLUSION

The prevalence of asymptomatic RHD in urban communities in Zambia is within the range of results reported in other sub-Saharan African countries using the WHF criteria. Task-shifting local radiographers to conduct echocardiography was feasible. The results of this study will be used to inform ongoing efforts in Zambia to control and eventually eliminate RHD.

TRIAL REGISTRATION

The study was registered on clinicaltrials.gov ( #NCT02661763 ).

ANIMA: Association network integration for multiscale analysis

Contextual functional interpretation of -omics data derived from clinical samples is a classical and difficult problem in computational systems biology. The measurement of thousands of data points on single samples has become routine but relating ‘big data’ datasets to the complexities of human pathobiology is an area of ongoing research. Complicating this is the fact that many publicly available datasets use bulk transcriptomics data from complex tissues like blood. The most prevalent analytic approaches derive molecular ‘signatures’ of disease states or apply modular analysis frameworks to the data. Here we describe ANIMA (association network integration for multiscale analysis), a network-based data integration method using clinical phenotype and microarray data as inputs. ANIMA is implemented in R and Neo4j and runs in Docker containers. In short, the build algorithm iterates over one or more transcriptomics datasets to generate a large, multipartite association network by executing multiple independent analytic steps (differential expression, deconvolution, modular analysis based on co-expression, pathway analysis) and integrating the results. Once the network is built, it can be queried directly using Cypher (a graph query language), or by custom functions that communicate with the graph database via language-specific APIs. We developed a web application using Shiny, which provides fully interactive, multiscale views of the data. Using our approach, we show that we can reconstruct multiple features of disease states at various scales of organization, from transcript abundance patterns of individual genes through co-expression patterns of groups of genes to patterns of cellular behaviour in whole blood samples, both in single experiments as well in meta-analyses of multiple datasets.