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True malaria prevalence in children under five: Bayesian estimation using data of malaria household surveys from three sub-Saharan countries.

ABSTRACT: BACKGROUND:Malaria is one of the major causes of childhood death in sub-Saharan countries. A reliable estimation of malaria prevalence is important to guide and monitor progress toward control and elimination. The aim of the study was to estimate the true prevalence of malaria in children under five in the Democratic Republic of the Congo, Uganda and Kenya, using a Bayesian modelling framework that combined in a novel way malaria data from national household surveys with external information about the sensitivity and specificity of the malaria diagnostic methods used in those surveys-i.e., rapid diagnostic tests and light microscopy. METHODS:Data were used from the Demographic and Health Surveys (DHS) and Malaria Indicator Surveys (MIS) conducted in the Democratic Republic of the Congo (DHS 2013-2014), Uganda (MIS 2014-2015) and Kenya (MIS 2015), where information on infection status using rapid diagnostic tests and/or light microscopy was available for 13,573 children. True prevalence was estimated using a Bayesian model that accounted for the conditional dependence between the two diagnostic methods, and the uncertainty of their sensitivities and specificities obtained from expert opinion. RESULTS:The estimated true malaria prevalence was 20% (95% uncertainty interval [UI] 17%-23%) in the Democratic Republic of the Congo, 22% (95% UI 9-32%) in Uganda and 1% (95% UI 0-3%) in Kenya. According to the model estimations, rapid diagnostic tests had a satisfactory sensitivity and specificity, and light microscopy had a variable sensitivity, but a satisfactory specificity. Adding reported history of fever in the previous 14 days as a third diagnostic method to the model did not affect model estimates, highlighting the poor performance of this indicator as a malaria diagnostic. CONCLUSIONS:In the absence of a gold standard test, Bayesian models can assist in the optimal estimation of the malaria burden, using individual results from several tests and expert opinion about the performance of those tests.

SUBMITTER: Mfueni E

PROVIDER: S-EPMC5800038 | biostudies-literature | 2018 Feb

REPOSITORIES: biostudies-literature

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True malaria prevalence in children under five: Bayesian estimation using data of malaria household surveys from three sub-Saharan countries.

Mfueni Elvire E Devleesschauwer Brecht B Rosas-Aguirre Angel A Van Malderen Carine C Brandt Patrick T PT Ogutu Bernhards B Snow Robert W RW Tshilolo Léon L Zurovac Dejan D Vanderelst Dieter D Speybroeck Niko N

Malaria journal 20180205 1

<h4>Background</h4>Malaria is one of the major causes of childhood death in sub-Saharan countries. A reliable estimation of malaria prevalence is important to guide and monitor progress toward control and elimination. The aim of the study was to estimate the true prevalence of malaria in children under five in the Democratic Republic of the Congo, Uganda and Kenya, using a Bayesian modelling framework that combined in a novel way malaria data from national household surveys with external informa ...[more]

PMID: 29402268

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Project description:BackgroundPlasmodium falciparum prevalence (PfPR) is a widely used metric for assessing malaria transmission intensity. This study was carried out concurrently with the RTS,S/AS01 candidate malaria vaccine Phase III trial and estimated PfPR over ≤ 4 standardized cross-sectional surveys.MethodsThis epidemiology study (NCT01190202) was conducted in 8 sites from 6 countries (Burkina Faso, Gabon, Ghana, Kenya, Malawi, and Tanzania), between March 2011 and December 2013. Participants were enrolled in a 2:1:1 ratio according to age category: 6 months-4 years, 5-19 years, and ≥ 20 years, respectively, per year and per centre. All sites carried out surveys 1-3 while survey 4 was conducted only in 3 sites. Surveys were usually performed during the peak malaria parasite transmission season, in one home visit, when medical history and malaria risk factors/prevention measures were collected, and a blood sample taken for rapid diagnostic test, microscopy, and haemoglobin measurement. PfPR was estimated by site and age category.ResultsOverall, 6401 (survey 1), 6411 (survey 2), 6400 (survey 3), and 2399 (survey 4) individuals were included in the analyses. In the 6 months-4 years age group, the lowest prevalence (assessed using microscopy) was observed in 2 Tanzanian centres (4.6% for Korogwe and 9.95% for Bagamoyo) and Lambaréné, Gabon (6.0%), while the highest PfPR was recorded for Nanoro, Burkina Faso (52.5%). PfPR significantly decreased over the 3 years in Agogo (Ghana), Kombewa (Kenya), Lilongwe (Malawi), and Bagamoyo (Tanzania), and a trend for increased PfPR was observed over the 4 surveys for Kintampo, Ghana. Over the 4 surveys, for all sites, PfPR was predominantly higher in the 5-19 years group than in the other age categories. Occurrence of fever and anaemia was associated with high P. falciparum parasitaemia. Univariate analyses showed a significant association of anti-malarial treatment in 4 surveys (odds ratios [ORs]: 0.52, 0.52, 0.68, 0.41) and bed net use in 2 surveys (ORs: 0.63, 0.68, 1.03, 1.78) with lower risk of malaria infection.ConclusionLocal PfPR differed substantially between sites and age groups. In children 6 months-4 years old, a significant decrease in prevalence over the 3 years was observed in 4 out of the 8 study sites. Trial registration Clinical Trials.gov identifier: NCT01190202:NCT. GSK Study ID numbers: 114001.

Project description:BackgroundThe annual collection of fertility, marriage, sexual behaviour, and contraceptive use data in the nationally representative rounds of Performance Monitoring and Accountability (PMA) surveys in sub-Saharan Africa may contribute to the periodic monitoring of adolescent sexual and reproductive health (ASRH). However, we need to understand the reliability of these data in monitoring the ASRH indicators. We assessed the internal and external consistencies in ASRH indicators in five countries.MethodsWe included countries with at least three nationally representative rounds of PMA surveys and two recent DHS: Ethiopia, Ghana, Kenya, Nigeria, and Uganda. Our analysis focused on four current status indicators of ASRH among girls 15-19 years: ever had sex, currently married, has given birth or currently pregnant, and currently using modern contraceptives among sexually active unmarried girls. We compared the PMA survey and DHS data and tested for statistical significance and assessed trends over time using Jonckheere-Terpstra test statistic.ResultsPMA and DHS survey methodologies were similar and, where there were differences, these were shown to have minimal impact on the indicator values. The comparison of the data points from PMA and DHS for the same years showed statistically significant differences in 12 of the 20 comparisons, which was most common for sexual behaviour (4/5) and least for contraceptive use (2/5). This is partly due to larger confidence intervals in both surveys. The time trends were consistent between the annual PMA surveys in most instances in Ethiopia, Kenya, and Nigeria but less so for Ghana and Uganda. However, both surveys highlight slow progress in adolescent and reproductive health indicators with major disparities between the countries.ConclusionsDespite the differences between PMA 2020 surveys and DHS surveys conducted in the same year, and inconsistencies of the PMA survey time series for several indicators in some countries, we found no systematic issues with PMA surveys and consider PMA surveys a valuable data source for the assessment of levels and trends of ASRH beyond contraceptive use and family planning for indicators of fertility, marriage, and sex among adolescent girls in sub-Saharan Africa.

Project description:BackgroundIn sub-Saharan Africa (SSA), millions of pregnant women are exposed to malaria infection. The cornerstone of the WHO strategy to prevent malaria in pregnancy in moderate to high-transmission areas is the administration of intermittent preventive treatment (IPTp) with sulfadoxine-pyrimethamine at each scheduled antenatal care (ANC) visit. However, overall coverage remains low. 'Transforming IPT for Optimal Pregnancy' (TIPTOP) project aims at delivering IPTp at the community level (C-IPTp) to complement ANC provision with the goal of increasing IPTp coverage and improving maternal and infant's health. This protocol describes the approach to measure the effect of this strategy through household surveys (HHS) in four SSA countries: Democratic Republic of Congo (DRC), Madagascar, Mozambique and Nigeria.Methods and analysisA quasi-experimental evaluation has been designed. Delivery of C-IPTp will start first in one area per country, and later it will be extended to two more areas per country. HHS will be carried out before C-IPTp implementation in all study sites, at midterm in initial implementation areas, and after the implementation in all project areas. A multistage cluster sampling method will be followed for the selection of participants. Women of reproductive age who had a pregnancy that ended in the 6 or 12 months prior to the interview, depending on the survey, will be invited to participate by responding to a questionnaire. The main indicators will be coverage of three or more doses of IPTp and attendance to at least four ANC visits. A difference-in-difference analysis will be performed to evaluate the effectiveness of C-IPTp.Ethics and disseminationThe project has been reviewed by the ethics committees of WHO, Hospital Clinic of Barcelona and all project country boards. Project results will be disseminated to in-country stakeholders and at regional and international meetings. TIPTOP project aims to develop and disseminate global recommendations for C-IPTp delivery.Trial registration numberNCT03600844; Pre-results.

Project description:The 2011 United Nations (UN) General Assembly Political Declaration on Prevention and Control of Non-Communicable Diseases (NCDs) brought NCDs to the global health agenda. Essential medicines are central to treating chronic diseases such as hypertension and diabetes. Our study aimed to quantify access to essential medicines for people with chronic conditions in five low- and middle-income countries and to evaluate how household socioeconomic status and perceptions about medicines availability and affordability influence access. We analysed data for 1867 individuals with chronic diseases from national surveys (Ghana, Jordan, Kenya, Philippines and Uganda) conducted in 2007-10 using a standard World Health Organization (WHO) methodology to measure medicines access and use. We defined individuals as having access to medicines if they reported regularly taking medicine for a diagnosed chronic disease and data collectors found a medicine indicated for that disease in their homes. We used logistic regression models accounting for the clustered survey design to investigate determinants of keeping medicines at home and predictors of access to medicines for chronic diseases. Less than half of individuals previously diagnosed with a chronic disease had access to medicines for their condition in every country, from 16% in Uganda to 49% in Jordan. Other than reporting a chronic disease, higher household socioeconomic level was the most significant predictor of having any medicines available at home. The likelihood of having access to medicines for chronic diseases was higher for those with medicines insurance coverage [highest adjusted odds ratio (OR) 3.12 (95% confidence intervals (CI): 1.38, 7.07)] and lower for those with past history of borrowing money to pay for medicines [lowest adjusted OR 0.56 (95% CI: 0.34, 0.92)]. Our study documents poor access to essential medicines for chronic conditions in five resource-constrained settings. It highlights the importance of financial risk protection and consumer education about generic medicines in global efforts towards improving treatment of chronic diseases.

Project description:IntroductionExtant studies universally document a positive gradient between socioeconomic status (SES) and health. A notable exception is the apparent concentration of HIV/AIDS among wealthier individuals. This paper uses data from the Demographic Health Surveys and AIDS Indicator Surveys to examine socioeconomic inequalities in HIV/AIDS prevalence in 24 sub-Saharan African (SSA) countries, the region that accounts for two-thirds of the global HIV/AIDS burden.MethodsThe relative and generalized concentration indices (RC and GC) were used to quantify wealth-based socioeconomic inequalities in HIV/AIDS prevalence for the total adult population (aged 15-49), for men and women, and in urban and rural areas in each country. Further, we decomposed the RC and GC indices to identify the determinants of socioeconomic inequalities in HIV/AIDS prevalence in each country.ResultsOur findings demonstrated that HIV/AIDS was concentrated among higher SES individuals in the majority of SSA countries. Swaziland and Senegal were the only countries in the region where HIV/AIDS was concentrated among individuals living in poorer households. Stratified analyses by gender showed HIV/AIDS was generally concentrated among wealthier men and women. In some countries, including Kenya, Lesotho Uganda, and Zambia, HIV/AIDS was concentrated among the poor in urban areas but among wealthier adults in rural areas. Decomposition analyses indicated that, besides wealth itself (median = 49%, interquartile range [IQR] = 90%), urban residence (median = 54%, IQR = 81%) was the most important factor contributing to the concentration of HIV/AIDS among wealthier participants in SSA countries.ConclusionsFurther work is needed to understand the mechanisms explaining the concentration of HIV/AIDS among wealthier individuals and urban residents in SSA. Higher prevalence of HIV/AIDS could be indicative of better care and survival among wealthier individuals and urban adults, or reflect greater risk behaviour and incidence. Moreover, differential findings across countries suggest that effective intervention efforts for reducing the burden of HIV/AIDS in the SSA should be country specific.

Dataset Information

True malaria prevalence in children under five: Bayesian estimation using data of malaria household surveys from three sub-Saharan countries.

Publications

True malaria prevalence in children under five: Bayesian estimation using data of malaria household surveys from three sub-Saharan countries.

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