| 1. |
- Adcock, Joanna, et al.
(author)
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The North-South information highway: case studies of publication access among health researchers in resource-poor countries
- 2008
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In: Global Health Action. - : CoAction Publishing. - 1654-9716 .- 1654-9880. ; 1
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Journal article (peer-reviewed)abstract
- Background: Less than 2% of scientific publications originate in low-income countries. Transfer of information from South to North and from South to South is grossly limited and hinders understanding of global health, while Northern-generated information fails to adequately address the needs of a Southern readership.Methods: A survey of a new generation of health researchers from nine low-income countries was conducted using a combination of email questionnaires and face-to-face interviews. Data were gathered on personal experiences, use and aspirations regarding access and contribution to published research.Results: A total of 23 individuals from 9 countries responded. Preference for journal use over textbooks was apparent, however a preference for print over online formats was described among African respondents compared to respondents from other areas. Almost all respondents (96%) described ambition to publish in international journals, but cited English language as a significant barrier.Conclusion: The desire to contribute to and utilise contemporary scientific debate appears to be strong among study respondents. However, longstanding barriers
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| 2. |
- Bird, J., et al.
(author)
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A matter of life and death : practical and ethical constraints in the development of a mobile verbal autopsy tool
- 2013
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In: CHI '13 Proceedings of the SIGCHI Conference on Human Factors in Computing SystemsPages 1489-1498. - New York, NY, USA : ACM. - 9781450318990 ; , s. 1489-1498
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Conference paper (peer-reviewed)abstract
- Verbal autopsy (VA) involves interviewing relatives of the deceased to identify the probable cause of death and is typically used in settings where there is no official system for recording deaths or their causes. Following the interview, physician assessment to determine probable cause can take several years to complete. The World Health Organization (WHO) recognizes that there is a pressing need for a mobile device that combines direct data capture and analysis if this technique is to become part of routine health surveillance. We conducted a field test in rural South Africa to evaluate a mobile system that we designed to meet WHO requirements (namely, simplicity, feasibility, adaptability to local contexts, cost-effectiveness and program relevance). If desired, this system can provide immediate feedback to respondents about the probable cause of death at the end of a VA interview. We assessed the ethical implications of this technological development by interviewing all the stakeholders in the VA process (respondents, fieldworkers, physicians, population scientists, data managers and community engagement managers) and highlight the issues that this community needs to debate and resolve.
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| 3. |
- Byass, Peter, et al.
(author)
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Comparing verbal autopsy cause of death findings as determined by physician coding and probabilistic modelling : a public health analysis of 54 000 deaths in Africa and Asia
- 2015
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In: Journal of Global Health. - 2047-2978 .- 2047-2986. ; 5:1, s. 65-73
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Journal article (peer-reviewed)abstract
- BACKGROUND: Coverage of civil registration and vital statistics varies globally, with most deaths in Africa and Asia remaining either unregistered or registered without cause of death. One important constraint has been a lack of fit-for-purpose tools for registering deaths and assigning causes in situations where no doctor is involved. Verbal autopsy (interviewing care-givers and witnesses to deaths and interpreting their information into causes of death) is the only available solution. Automated interpretation of verbal autopsy data into cause of death information is essential for rapid, consistent and affordable processing.METHODS: Verbal autopsy archives covering 54 182 deaths from five African and Asian countries were sourced on the basis of their geographical, epidemiological and methodological diversity, with existing physician-coded causes of death attributed. These data were unified into the WHO 2012 verbal autopsy standard format, and processed using the InterVA-4 model. Cause-specific mortality fractions from InterVA-4 and physician codes were calculated for each of 60 WHO 2012 cause categories, by age group, sex and source. Results from the two approaches were assessed for concordance and ratios of fractions by cause category. As an alternative metric, the Wilcoxon matched-pairs signed ranks test with two one-sided tests for stochastic equivalence was used.FINDINGS: The overall concordance correlation coefficient between InterVA-4 and physician codes was 0.83 (95% CI 0.75 to 0.91) and this increased to 0.97 (95% CI 0.96 to 0.99) when HIV/AIDS and pulmonary TB deaths were combined into a single category. Over half (53%) of the cause category ratios between InterVA-4 and physician codes by source were not significantly different from unity at the 99% level, increasing to 62% by age group. Wilcoxon tests for stochastic equivalence also demonstrated equivalence.CONCLUSIONS: These findings show strong concordance between InterVA-4 and physician-coded findings over this large and diverse data set. Although these analyses cannot prove that either approach constitutes absolute truth, there was high public health equivalence between the findings. Given the urgent need for adequate cause of death data from settings where deaths currently pass unregistered, and since the WHO 2012 verbal autopsy standard and InterVA-4 tools represent relatively simple, cheap and available methods for determining cause of death on a large scale, they should be used as current tools of choice to fill gaps in cause of death data.
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| 4. |
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| 5. |
- Byass, Peter, et al.
(author)
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Moving from data on deaths to public health policy in Agincourt, South Africa : approaches to analysing and understanding verbal autopsy findings
- 2010
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In: PLoS Medicine. - : Public Library of Science. - 1549-1277 .- 1549-1676. ; 7:8, s. e1000325-
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Journal article (peer-reviewed)abstract
- There were no differences between physician interpretation and probabilistic modelling that might have led to substantially different public health policy conclusions at the population level. Physician interpretation was more nuanced than the model, for example in identifying cancers at particular sites, but did not capture the uncertainty associated with individual cases. Probabilistic modelling was substantially cheaper and faster, and completely internally consistent. Both approaches characterised the rise of HIV-related mortality in this population during the period observed, and reached similar findings on other major causes of mortality. For many purposes probabilistic modelling appears to be the best available means of moving from data on deaths to public health actions. Please see later in the article for the Editors' Summary.
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| 6. |
- Byass, Peter, et al.
(author)
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Refining a probabilistic model for interpreting verbal autopsy data.
- 2006
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In: Scandinavian journal of public health. - : SAGE Publications. - 1403-4948 .- 1651-1905. ; 34:1, s. 26-31
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Journal article (peer-reviewed)abstract
- Objective: To build on the previously reported development of a Bayesian probabilistic model for interpreting verbal autopsy (VA) data, attempting to improve the model's performance in determining cause of death and to reassess it. Design: An expert group of clinicians, coming from a wide range geographically and in terms of specialization, was convened. Over a four-day period the content of the previous probabilistic model was reviewed in detail and adjusted as necessary to reflect the group consensus. The revised model was tested with the same 189 VA cases from Vietnam, assessed by two local clinicians, that were used to test the preliminary model. Results: The revised model contained a total of 104 indicators that could be derived from VA data and 34 possible causes of death. When applied to the 189 Vietnamese cases, 142 (75.1%) achieved concordance between the model's output and the previous clinical consensus. The remaining 47 cases (24.9%) were presented to a further independent clinician for reassessment. As a result, consensus between clinical reassessment and the model's output was achieved in 28 cases (14.8%); clinical reassessment and the original clinical opinion agreed in 8 cases (4.2%), and in the remaining 11 cases (5.8%) clinical reassessment, the model, and the original clinical opinion all differed. Thus overall the model was considered to have performed well in 170 cases (89.9%). Conclusions: This approach to interpreting VA data continues to show promise. The next steps will be to evaluate it against other sources of VA data. The expert group approach to determining the required probability base seems to have been a productive one in improving the performance of the model.
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| 7. |
- Byass, Peter, et al.
(author)
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Strengthening standardised interpretation of verbal autopsy data : the new InterVA-4 tool
- 2012
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In: Global Health Action. - Järfälla, Sweden : CoAction Publishing. - 1654-9716 .- 1654-9880. ; 5
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Journal article (peer-reviewed)abstract
- Background: Verbal autopsy (VA) is the only available approach for determining the cause of many deaths, where routine certification is not in place. Therefore, it is important to use standards and methods for VA that maximise efficiency, consistency and comparability. The World Health Organization (WHO) has led the development of the 2012 WHO VA instrument as a new standard, intended both as a research tool and for routine registration of deaths. Objective: A new public-domain probabilistic model for interpreting VA data, InterVA-4, is described, which builds on previous versions and is aligned with the 2012 WHO VA instrument. Design: The new model has been designed to use the VA input indicators defined in the 2012 WHO VA instrument and to deliver causes of death compatible with the International Classification of Diseases version 10 (ICD-10) categorised into 62 groups as defined in the 2012 WHO VA instrument. In addition, known shortcomings of previous InterVA models have been addressed in this revision, as well as integrating other work on maternal and perinatal deaths. Results: The InterVA-4 model is presented here to facilitate its widespread use and to enable further field evaluation to take place. Results from a demonstration dataset from Agincourt, South Africa, show continuity of interpretation between InterVA-3 and InterVA-4, as well as differences reflecting specific issues addressed in the design and development of InterVA-4. Conclusions: InterVA-4 is made freely available as a new standard model for interpreting VA data into causes of death. It can be used for determining cause of death both in research settings and for routine registration. Further validation opportunities will be explored. These developments in cause of death registration are likely to substantially increase the global coverage of cause-specific mortality data.
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| 8. |
- Byass, Peter, et al.
(author)
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Using verbal autopsy to track epidemic dynamics : the case of HIV-related mortality in South Africa.
- 2011
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In: Population Health Metrics. - : BioMed Central (BMC). - 1478-7954. ; 9, s. 46-
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Journal article (peer-reviewed)abstract
- Background Verbal autopsy (VA) has often been used for point estimates of cause-specific mortality, but seldom to characterize long-term changes in epidemic patterns. Monitoring emerging causes of death involves practitioners' developing perceptions of diseases and demands consistent methods and practices. Here we retrospectively analyze HIV-related mortality in South Africa, using physician and modeled interpretation.Methods Between 1992 and 2005, 94% of 6,153 deaths which occurred in the Agincourt subdistrict had VAs completed, and coded by two physicians and the InterVA model. The physician causes of death were consolidated into a single consensus underlying cause per case, with an additional physician arbitrating where different diagnoses persisted. HIV-related mortality rates and proportions of deaths coded as HIV-related by individual physicians, physician consensus, and the InterVA model were compared over time.Results Approximately 20% of deaths were HIV-related, ranging from early low levels to tenfold-higher later population rates (2.5 per 1,000 person-years). Rates were higher among children under 5 years and adults 20 to 64 years. Adult mortality shifted to older ages as the epidemic progressed, with a noticeable number of HIV-related deaths in the over-65 year age group latterly. Early InterVA results suggested slightly higher initial HIV-related mortality than physician consensus found. Overall, physician consensus and InterVA results characterized the epidemic very similarly. Individual physicians showed marked interobserver variation, with consensus findings generally reflecting slightly lower proportions of HIV-related deaths. Aggregated findings for first versus second physician did not differ appreciably.Conclusions VA effectively detected a very significant epidemic of HIV-related mortality. Using either physicians or InterVA gave closely comparable findings regarding the epidemic. The consistency between two physician coders per case (from a pool of 14) suggests that double coding may be unnecessary, although the consensus rate of HIV-related mortality was approximately 8% lower than by individual physicians. Consistency within and between individual physicians, individual perceptions of epidemic dynamics, and the inherent consistency of models are important considerations here. The ability of the InterVA model to track a more than tenfold increase in HIV-related mortality over time suggests that finely tuned "local" versions of models for VA interpretation are not necessary.
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| 9. |
- D'Ambruoso, Lucia, et al.
(author)
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Refining circumstances of mortality categories (COMCAT): a verbal autopsy model connecting circumstances of deaths with outcomes for public health decision-making
- 2021
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In: Global Health Action. - : Taylor & Francis. - 1654-9716 .- 1654-9880. ; 14
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Journal article (peer-reviewed)abstract
- BACKGROUND: Recognising that the causes of over half the world's deaths pass unrecorded, the World Health Organization (WHO) leads development of Verbal Autopsy (VA): a method to understand causes of death in otherwise unregistered populations. Recently, VA has been developed for use outside research environments, supporting countries and communities to recognise and act on their own health priorities. We developed the Circumstances of Mortality Categories (COMCATs) system within VA to provide complementary circumstantial categorisations of deaths.OBJECTIVES: Refine the COMCAT system to (a) support large-scale population assessment and (b) inform public health decision-making.METHODS: We analysed VA data for 7,980 deaths from two South African Health and Socio-Demographic Surveillance Systems (HDSS) from 2012 to 2019: the Agincourt HDSS in Mpumalanga and the Africa Health Research Institute HDSS in KwaZulu-Natal. We assessed the COMCAT system's reliability (consistency over time and similar conditions), validity (the extent to which COMCATs capture a sufficient range of key circumstances and events at and around time of death) and relevance (for public health decision-making).RESULTS: Plausible results were reliably produced, with 'emergencies', 'recognition, 'accessing care' and 'perceived quality' characterising the majority of avoidable deaths. We identified gaps and developed an additional COMCAT 'referral', which accounted for a significant proportion of deaths in sub-group analysis. To support decision-making, data that establish an impetus for action, that can be operationalised into interventions and that capture deaths outside facilities are important.CONCLUSIONS: COMCAT is a pragmatic, scalable approach enhancing functionality of VA providing basic information, not available from other sources, on care seeking and utilisation at and around time of death. Continued development with stakeholders in health systems, civil registration, community and research environments will further strengthen the tool to capture social and health systems drivers of avoidable deaths and promote use in practice settings.
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| 10. |
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| 11. |
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| 12. |
- Filippi, Véronique, et al.
(author)
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Effects of severe obstetric complications on women's health and infant mortality in Benin
- 2010
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In: Tropical medicine & international health. - : Wiley. - 1360-2276 .- 1365-3156. ; 15:6, s. 733-742
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Journal article (peer-reviewed)abstract
- Women in developing countries face a high risk of severe complications during pregnancy and delivery. These can lead to adverse consequences for their own health and that of their offspring. Resources are needed to ensure that pregnant women receive adequate care before, during and after discharge from hospital. Near-miss women with a perinatal death appear a particularly high-risk group.
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| 13. |
- Fottrell, Edward, et al.
(author)
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A probabilistic method to estimate the burden of maternal morbidity in resource-poor settings : preliminary development and evaluation
- 2014
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In: Emerging Themes in Epidemiology. - : BioMed Central (BMC). - 1742-7622. ; 11:1, s. 3-
-
Journal article (peer-reviewed)abstract
- BACKGROUND: Maternal morbidity is more common than maternal death, and population-based estimates of the burden of maternal morbidity could provide important indicators for monitoring trends, priority setting and evaluating the health impact of interventions. Methods based on lay reporting of obstetric events have been shown to lack specificity and there is a need for new approaches to measure the population burden of maternal morbidity. A computer-based probabilistic tool was developed to estimate the likelihood of maternal morbidity and its causes based on self-reported symptoms and pregnancy/delivery experiences. Development involved the use of training datasets of signs, symptoms and causes of morbidity from 1734 facility-based deliveries in Benin and Burkina Faso, as well as expert review. Preliminary evaluation of the method compared the burden of maternal morbidity and specific causes from the probabilistic tool with clinical classifications of 489 recently-delivered women from Benin, Bangladesh and India.RESULTS: Using training datasets, it was possible to create a probabilistic tool that handled uncertainty of women's self reports of pregnancy and delivery experiences in a unique way to estimate population-level burdens of maternal morbidity and specific causes that compared well with clinical classifications of the same data. When applied to test datasets, the method overestimated the burden of morbidity compared with clinical review, although possible conceptual and methodological reasons for this were identified.CONCLUSION: The probabilistic method shows promise and may offer opportunities for standardised measurement of maternal morbidity that allows for the uncertainty of women's self-reported symptoms in retrospective interviews. However, important discrepancies with clinical classifications were observed and the method requires further development, refinement and evaluation in a range of settings.
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| 14. |
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| 15. |
- Fottrell, Edward, et al.
(author)
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Demonstrating the robustness of population surveillance data : implications of error rates on demographic and mortality estimates
- 2008
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In: BMC Medical Research Methodology. - : BioMed Central. - 1471-2288. ; 8, s. Article nr 13-
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Journal article (peer-reviewed)abstract
- BACKGROUND: As in any measurement process, a certain amount of error may be expected in routine population surveillance operations such as those in demographic surveillance sites (DSSs). Vital events are likely to be missed and errors made no matter what method of data capture is used or what quality control procedures are in place. The extent to which random errors in large, longitudinal datasets affect overall health and demographic profiles has important implications for the role of DSSs as platforms for public health research and clinical trials. Such knowledge is also of particular importance if the outputs of DSSs are to be extrapolated and aggregated with realistic margins of error and validity.METHODS: This study uses the first 10-year dataset from the Butajira Rural Health Project (BRHP) DSS, Ethiopia, covering approximately 336,000 person-years of data. Simple programmes were written to introduce random errors and omissions into new versions of the definitive 10-year Butajira dataset. Key parameters of sex, age, death, literacy and roof material (an indicator of poverty) were selected for the introduction of errors based on their obvious importance in demographic and health surveillance and their established significant associations with mortality. Defining the original 10-year dataset as the 'gold standard' for the purposes of this investigation, population, age and sex compositions and Poisson regression models of mortality rate ratios were compared between each of the intentionally erroneous datasets and the original 'gold standard' 10-year data.RESULTS: The composition of the Butajira population was well represented despite introducing random errors, and differences between population pyramids based on the derived datasets were subtle. Regression analyses of well-established mortality risk factors were largely unaffected even by relatively high levels of random errors in the data.CONCLUSION: The low sensitivity of parameter estimates and regression analyses to significant amounts of randomly introduced errors indicates a high level of robustness of the dataset. This apparent inertia of population parameter estimates to simulated errors is largely due to the size of the dataset. Tolerable margins of random error in DSS data may exceed 20%. While this is not an argument in favour of poor quality data, reducing the time and valuable resources spent on detecting and correcting random errors in routine DSS operations may be justifiable as the returns from such procedures diminish with increasing overall accuracy. The money and effort currently spent on endlessly correcting DSS datasets would perhaps be better spent on increasing the surveillance population size and geographic spread of DSSs and analysing and disseminating research findings.
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| 16. |
- Fottrell, Edward
(author)
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Dying to count : mortality surveillance in resource-poor settings
- 2009
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In: Global Health Action. - : CoAction Publishing. - 1654-9716 .- 1654-9880. ; 2
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Journal article (peer-reviewed)abstract
- Reliable cause-specific mortality data constitute a crucial resource for health monitoring, service planning and prioritisation. However, in the majority of the world's poorest settings, systematic health and vital event surveillance systems are weak or non-existent. As such, deaths are not counted and causes of death remain unregistered for more than two-thirds of the world's population.For researchers, health workers and policy makers in resource-poor settings, therefore, attempts to measure mortality have to be implemented from first principles. As a result, there is wide variation in mortality surveillance methodologies in different settings, and lack of standardisation and rigorous validation of these methods hinder meaningful comparison of mortality data between settings and over time.With a particular focus on Health and Demographic Surveillance Systems (HDSSs), this paper summarises recent research and conceptual development of certain methodological aspects of mortality surveillance stemming from a series of empirical investigations. The paper describes the advantages and limitations of various methods in particular contexts, and argues that there is no single methodology to satisfy all data needs. Rather, methodological decisions about mortality measurement should be a synthesis of all available knowledge relating to clearly defined concepts of why data are being collected, how they can be used and when they are of good enough quality to inform public health action.
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| 17. |
- Fottrell, Edward F, 1980-
(author)
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Dying to count : mortality surveillance methods in resource-poor settings
- 2008
-
Doctoral thesis (other academic/artistic)abstract
- Background Mortality data are critical to understanding and monitoring changes in population health status over time. Nevertheless, the majority of people living in the world’s poorest countries, where the burden of disease is highest, remain outside any kind of systematic health surveillance. This lack of routine registration of vital events, such as births and deaths, constitutes a major and longstanding constraint on the understanding of patterns of health and disease and the effectiveness of interventions. Localised sentinel demographic and health surveillance strategies are a useful surrogate for more widespread surveillance in such settings, but rigorous, evidence-based methodologies for sample-based surveillance are weak and by no means standardised. This thesis aims to describe, evaluate and refine methodological approaches to mortality measurement in resource-poor settings. Methods Through close collaboration with existing community surveillance operations in a range of settings, this work uses existing data from demographic surveillance sites and community-based surveys using various innovative approaches in order to evaluate and refine methodological approaches to mortality measurement and cause-of-death determination. In doing so, this work explores the application of innovative techniques and procedures for mortality surveillance in relation to the differing needs of those who use mortality data, ranging from global health organisations to local health planners. Results Empirical modelling of sampling procedures in community-based surveys in rural Africa and of random errors in longitudinal data collection sheds light on the effects of various data-capture and quality-control procedures and demonstrates the representativeness and robustness of population surveillance datasets. The development, application and refinement of a probabilistic approach to determining causes of death at the population level in developing countries has shown promise in overcoming the longstanding limitations and issues of standardisation of existing methods. Further adaptation and application of this approach to measure maternal deaths has also been successful. Application of international guidelines on humanitarian crisis detection to mortality surveillance in Ethiopia demonstrates that simple procedures can and, from an ethical perspective, should be applied to sentinel surveillance methods for the prospective detection of important mortality changes in vulnerable populations. Conclusion Mortality surveillance in sentinel surveillance systems in resource-poor settings is a valuable and worthwhile task. This work contributes to the understanding of the effects of different methods of surveillance and demonstrates that, ultimately, the choice of methods for collecting data, assuring data quality and determining causes of death depends on the specific needs and requirements of end users. Surveillance systems have the potential to contribute substantially to developing health care systems in resource-poor countries and should not only be considered as research-oriented enterprises.
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| 18. |
- Fottrell, Edward, et al.
(author)
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Identifying humanitarian crises in population surveillance field sites : simple procedures and ethical imperatives.
- 2009
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In: Public Health. - : Elsevier BV. - 0033-3506 .- 1476-5616. ; 123:2, s. 151-155
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Journal article (peer-reviewed)abstract
- OBJECTIVES: Effective early warning systems of humanitarian crises may help to avert substantial increases in mortality and morbidity, and prevent major population movements. The Butajira Rural Health Programme (BRHP) in Ethiopia has maintained a programme of epidemiological surveillance since 1987. Inspection of the BRHP data revealed large peaks of mortality in 1998 and 1999, well in excess of the normally observed year-to-year variation. Further investigation and enquiry revealed that these peaks related to a measles epidemic, and a serious episode of drought and consequent food insecurity that went undetected by the BRHP. This paper applies international humanitarian crisis threshold definitions to the BRHP data in an attempt to identify suitable mortality thresholds that may be used for the prospective detection of humanitarian crises in population surveillance sites in developing countries. STUDY DESIGN: Empirical investigation using secondary analysis of longitudinal population-based cohort data. METHODS: The daily, weekly and monthly thresholds for crises in Butajira were applied to mortality data for the 5-year period incorporating the crisis periods of 1998-1999. Days, weeks and months in which mortality exceeded each threshold level were identified. Each threshold level was assessed in terms of prospectively identifying the true crisis periods in a timely manner whilst avoiding false alarms. RESULTS: The daily threshold definition is too sensitive to accurately detect impending or real crises in the population surveillance setting of the BRHP. However, the weekly threshold level is useful in identifying important increases in mortality in a timely manner without the excessive sensitivity of the daily threshold. The weekly threshold level detects the crisis periods approximately 2 weeks before the monthly threshold level. CONCLUSION: Mortality measures are highly specific indicators of the health status of populations, and simple procedures can be used to apply international crisis threshold definitions in population surveillance settings for the prospective detection of important changes in mortality rate. Standards for the timely use of surveillance data and ethical responsibilities of those responsible for the data should be made explicit to improve the public health functioning of current sentinel surveillance methodologies.
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| 19. |
- Fottrell, Edward, et al.
(author)
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Mortality measurement in transition : proof of principle for standardised multi-country comparisons
- 2010
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In: Tropical medicine & international health. - : Wiley. - 1360-2276 .- 1365-3156. ; 15:10, s. 1256-1265
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Journal article (peer-reviewed)abstract
- Given the standardised method of VA interpretation, the observed differences in mortality cannot be because of local differences in assigning cause of death. Standardised, fit-for-purpose methods are needed to measure population health and changes in mortality patterns so that appropriate health policy and programmes can be designed, implemented and evaluated over time and place. The InterVA approach overcomes several longstanding limitations of existing methods and represents a valuable tool for health planners and researchers in resource-poor settings.
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| 20. |
- Fottrell, Edward, et al.
(author)
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Population survey sampling methods in a rural African setting : measuring mortality
- 2008
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In: Population Health Metrics. - : BioMed Central (BMC). - 1478-7954. ; 6, s. Article nr 2-
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Journal article (peer-reviewed)abstract
- BACKGROUND: Population-based sample surveys and sentinel surveillance methods are commonly used as substitutes for more widespread health and demographic monitoring and intervention studies in resource-poor settings. Such methods have been criticised as only being worthwhile if the results can be extrapolated to the surrounding 100-fold population. With an emphasis on measuring mortality, this study explores the extent to which choice of sampling method affects the representativeness of 1% sample data in relation to various demographic and health parameters in a rural, developing-country setting.METHODS: Data from a large community based census and health survey conducted in rural Burkina Faso were used as a basis for modelling. Twenty 1% samples incorporating a range of health and demographic parameters were drawn at random from the overall dataset for each of seven different sampling procedures at two different levels of local administrative units. Each sample was compared with the overall 'gold standard' survey results, thus enabling comparisons between the different sampling procedures.RESULTS: All sampling methods and parameters tested performed reasonably well in representing the overall population. Nevertheless, a degree of variation could be observed both between sampling approaches and between different parameters, relating to their overall distribution in the total population.CONCLUSION: Sample surveys are able to provide useful demographic and health profiles of local populations. However, various parameters being measured and their distribution within the sampling unit of interest may not all be best represented by a particular sampling method. It is likely therefore that compromises may have to be made in choosing a sampling strategy, with costs, logistics the intended use of the data being important considerations.
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| 21. |
- Fottrell, Edward, et al.
(author)
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Probabilistic methods for verbal autopsy interpretation : InterVA robustness in relation to variations in a priori probabilities
- 2011
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In: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 6:11, s. e27200-
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Journal article (peer-reviewed)abstract
- Background: InterVA is a probabilistic method for interpreting verbal autopsy (VA) data. It uses a priori approximations of probabilities relating to diseases and symptoms to calculate the probability of specific causes of death given reported symptoms recorded in a VA interview. The extent to which InterVA's ability to characterise a population's mortality composition might be sensitive to variations in these a priori probabilities was investigated.Methods: A priori InterVA probabilities were changed by 1, 2 or 3 steps on the logarithmic scale on which the original probabilities were based. These changes were made to a random selection of 25% and 50% of the original probabilities, giving six model variants. A random sample of 1,000 VAs from South Africa, were used as a basis for experimentation and were processed using the original InterVA model and 20 random instances of each of the six InterVA model variants. Rank order of cause of death and cause-specific mortality fractions (CSMFs) from the original InterVA model and the mean, maximum and minimum results from the 20 randomly modified InterVA models for each of the six variants were compared.Results: CSMFs were functionally similar between the original InterVA model and the models with modified a priori probabilities such that even the CSMFs based on the InterVA model with the greatest degree of variation in the a priori probabilities would not lead to substantially different public health conclusions. The rank order of causes were also similar between all versions of InterVA.Conclusion: InterVA is a robust model for interpreting VA data and even relatively large variations in a priori probabilities do not affect InterVA-derived results to a great degree. The original physician-derived a priori probabilities are likely to be sufficient for the global application of InterVA in settings without routine death certification.
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| 22. |
- Fottrell, Edward, et al.
(author)
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Revealing the burden of maternal mortality : a probabilistic model for determining pregnancy-related causes of death from verbal autopsies
- 2007
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In: Population Health Metrics. - : BioMed Central (BMC). - 1478-7954. ; 5:1
-
Journal article (peer-reviewed)abstract
- Background: Substantial reductions in maternal mortality are called for in Millennium Development Goal 5 (MDG-5), thus assuming that maternal mortality is measurable. A key difficulty is attributing causes of death for the many women who die unaided in developing countries. Verbal autopsy (VA) can elicit circumstances of death, but data need to be interpreted reliably and consistently to serve as global indicators. Recent developments in probabilistic modelling of VA interpretation are adapted and assessed here for the specific circumstances of pregnancy-related death.Methods: A preliminary version of the InterVA-M probabilistic VA interpretation model was developed and refined with adult female VA data from several sources, and then assessed against 258 additional VA interviews from Burkina Faso. Likely causes of death produced by the model were compared with causes previously determined by local physicians. Distinction was made between free-text and closed-question data in the VA interviews, to assess the added value of free-text material on the model's output.Results: Following rationalisation between the model and physician interpretations, cause-specific mortality fractions were broadly similar. Case-by-case agreement between the model and any of the reviewing physicians reached approximately 60%, rising to approximately 80% when cases with a discrepancy were reviewed by an additional physician. Cardiovascular disease and malaria showed the largest differences between the methods, and the attribution of infections related to pregnancy also varied. The model estimated 30% of deaths to be pregnancy-related, of which half were due to direct causes. Data derived from free-text made no appreciable difference.Conclusion: InterVA-M represents a potentially valuable new tool for measuring maternal mortality in an efficient, consistent and standardised way. Further development, refinement and validation are planned. It could become a routine tool in research and service settings where levels and changes in pregnancy-related deaths need to be measured, for example in assessing progress towards MDG-5.
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| 23. |
- Fottrell, Edward, et al.
(author)
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Risk of psychological distress following severe obstetric complications in Benin : the role of economics, physical health and spousal abuse
- 2010
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In: British Journal of Psychiatry. - : Royal College of Psychiatrists. - 0007-1250 .- 1472-1465. ; 196:1, s. 18-25
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Journal article (peer-reviewed)abstract
- BACKGROUND: Little is known about the impact of life-threatening obstetric complications ('near miss') on women's mental health in low- and middle-income countries.AIMS: To examine the relationships between near miss and postpartum psychological distress in the Republic of Benin. METHOD: One-year prospective cohort using epidemiological and ethnographic techniques in a population of women delivering at health facilities.RESULTS: In total 694 women contributed to the study. Except when associated with perinatal death, near-miss events were not associated with greater risk of psychological distress in the 12 months postpartum compared with uncomplicated childbirth. Much of the direct effect of near miss with perinatal death on increased risk of psychological distress was shown to be mediated through wider consequences of traumatic childbirth.CONCLUSIONS: A live baby protects near-miss women from increased vulnerability by giving a positive element in their lives that helps them cope and reduces their risk of psychological distress. Near-miss women with perinatal death should be targeted early postpartum to prevent or treat the development of depressive symptoms.
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| 24. |
- Fottrell, Edward, et al.
(author)
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Sickle Cell Anaemia in a Changing World
- 2013
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In: PLoS Medicine. - : Public Library of Science (PLoS). - 1549-1277 .- 1549-1676. ; 10:7, s. e1001483-
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Journal article (other academic/artistic)
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| 25. |
- Fottrell, Edward, et al.
(author)
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The distribution and effects of child mortality risk factors in Ethiopia : a comparison of estimates from DSS and DHS
- 2009
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In: Ethiopian Journal of Health Development. - : Ethiopian Public Health Association. - 1021-6790 .- 2309-7388. ; 23:2, s. 163-168
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Journal article (peer-reviewed)abstract
- Objectives: To conduct a comparative analysis of the distribution and effects of under-five mortality correlates using Demographic and Health Survey (DHS) and Demographic Surveillance System (DSS) data from Ethiopia, and to investigate the methodological bias in DHS-based childhood mortality rates due to the impossibility of including children whose mothers were deceased.Methods: Using all-cause under-5 mortality as an outcome variable, the distribution and effects of risk factors were modeled using survival analysis. All live births in rural Ethiopia in the 5-year period before the 2005 DSS+ survey and between 01/01/2000 and 31/12/2004 in the DSS in the Butajira Rural Health Program (in the Southern Nations, Nationalities, and People's (SNNP) region of Ethiopia) were included.Results: Overall, similar estimates of hazard rate ratios were derived from both DHS and DSS data and the child mortality risk profile is similar between each data source, with multiple births and living in less populous households being significant risk factors for under-five mortality. Nevertheless, some notable differences were observed. The DSS data was more sensitive to local variations in population composition and health status, whilst the more dispersed DHS approach tended to average out local variation across the country. Excluding children whose mothers were deceased from the DSS analysis had no important effect on risk profiles or estimates of survival functions at age 5 years. DHS survival functions were somewhat lower than DSS estimates (BRHP=0.87, DHS rural Ethiopia=0.67, DHS SNNP=0.66).Conclusion: Despite differing methodologies, cross-sectional DHS and longitudinal DSS data produce estimates of the distribution and effects of under-five mortality risk factors that are broadly similar. The differing methodological characteristics of DHS and DSS mean that when combined, these two data sources have the potential to provide a comprehensive picture of national population composition and health status as well as the extent of local variation both of which are important for health monitoring and planning.
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