Modelling the incremental benefit of introducing malaria screening strategies to antenatal care in Africa.
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ABSTRACT:
SUBMITTER: Walker PGT
PROVIDER: S-EPMC7393377 | biostudies-literature | 2020 Jul
REPOSITORIES: biostudies-literature
Publications
Modelling the incremental benefit of introducing malaria screening strategies to antenatal care in Africa.
Walker Patrick G T PGT Cairns Matt M Slater Hannah H Gutman Julie J Kayentao Kassoum K Williams John E JE Coulibaly Sheick O SO Khairallah Carole C Taylor Steve S Meshnick Steven R SR Hill Jenny J Mwapasa Victor V Kalilani-Phiri Linda L Bojang Kalifa K Kariuki Simon S Tagbor Harry H Griffin Jamie T JT Madanitsa Mwayi M Ghani Azra C H ACH Desai Meghna M Ter Kuile Feiko O FO
Nature communications 20200730 1
Plasmodium falciparum in pregnancy is a major cause of adverse pregnancy outcomes. We combine performance estimates of standard rapid diagnostic tests (RDT) from trials of intermittent screening and treatment in pregnancy (ISTp) with modelling to assess whether screening at antenatal visits improves upon current intermittent preventative therapy with sulphadoxine-pyrimethamine (IPTp-SP). We estimate that RDTs in primigravidae at first antenatal visit are substantially more sensitive than in non- ...[more]
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Project description:A study found screening (with rapid plasma reagin (RPR)) pregnant women for maternal syphilis was cost-effective in Mwanza, Tanzania. Recently, four rapid point-of-care (POC) syphilis tests were evaluated in Mwanza, and found to have reasonable sensitivity/specificity. This analysis estimates the relative cost-effectiveness of using these POC tests in the Mwanza syphilis screening intervention.Empirical cost and epidemiological data were used to model the potential benefit of using POC tests instead of RPR. Reductions in costs relating to training, supplies, and equipment were estimated, and any changes in impact due to test sensitivity were included. Additional modelling explored how the results vary with prevalence of past infection, misclassified RPR results, and if not all women return for treatment.The cost-effectiveness of using POC tests is mainly dependent on their cost and sensitivity for high titre active syphilis (HTAS). Savings due to reductions in training and equipment are small. Current POC tests may save more disability-adjusted life years (DALYs) than the RPR test in Mwanza, but the test cost needs to be <0.63 US dollars to be as cost-effective as RPR. However, the cost-effectiveness of the RPR test worsens by 15% if its HTAS sensitivity had been 75% instead of 86%, and by 25-65% if 20-40% of women had not returned for treatment. In such settings, POC tests could improve cost-effectiveness. Lastly, the cost-effectiveness of POC tests is affected little by the prevalence of syphilis, false RPR-positives, and past infections.Although the price of most POC tests needs to be reduced to make them as cost-effective as RPR, their simplicity and limited requirements for electricity/equipment suggest their use could improve the coverage of antenatal syphilis screening in developing countries.
| S-EPMC2563909 | biostudies-other
Project description:BackgroundThe RTS,S/AS01 vaccine against Plasmodium falciparum malaria infection completed phase III trials in 2014 and demonstrated efficacy against clinical malaria of approximately 36% over 4 years for a 4-dose schedule in children aged 5-17 months. Pilot vaccine implementation has recently begun in 3 African countries. If the pilots demonstrate both a positive health impact and resolve remaining safety concerns, wider roll-out could be recommended from 2021 onwards. Vaccine demand may, however, outstrip initial supply. We sought to identify where vaccine introduction should be prioritised to maximise public health impact under a range of supply constraints using mathematical modelling.Methods and findingsUsing a mathematical model of P. falciparum malaria transmission and RTS,S vaccine impact, we estimated the clinical cases and deaths averted in children aged 0-5 years in sub-Saharan Africa under 2 scenarios for vaccine coverage (100% and realistic) and 2 scenarios for other interventions (current coverage and World Health Organization [WHO] Global Technical Strategy targets). We used a prioritisation algorithm to identify potential allocative efficiency gains from prioritising vaccine allocation among countries or administrative units to maximise cases or deaths averted. If malaria burden at introduction is similar to current levels-assuming realistic vaccine coverage and country-level prioritisation in areas with parasite prevalence >10%-we estimate that 4.3 million malaria cases (95% credible interval [CrI] 2.8-6.8 million) and 22,000 deaths (95% CrI 11,000-35,000) in children younger than 5 years could be averted annually at a dose constraint of 30 million. This decreases to 3.0 million cases (95% CrI 2.0-4.7 million) and 14,000 deaths (95% CrI 7,000-23,000) at a dose constraint of 20 million, and increases to 6.6 million cases (95% CrI 4.2-10.8 million) and 38,000 deaths (95% CrI 18,000-61,000) at a dose constraint of 60 million. At 100% vaccine coverage, these impact estimates increase to 5.2 million cases (95% CrI 3.5-8.2 million) and 27,000 deaths (95% CrI 14,000-43,000), 3.9 million cases (95% CrI 2.7-6.0 million) and 19,000 deaths (95% CrI 10,000-30,000), and 10.0 million cases (95% CrI 6.7-15.7 million) and 51,000 deaths (95% CrI 25,000-82,000), respectively. Under realistic vaccine coverage, if the vaccine is prioritised sub-nationally, 5.3 million cases (95% CrI 3.5-8.2 million) and 24,000 deaths (95% CrI 12,000-38,000) could be averted at a dose constraint of 30 million. Furthermore, sub-national prioritisation would allow introduction in almost double the number of countries compared to national prioritisation (21 versus 11). If vaccine introduction is prioritised in the 3 pilot countries (Ghana, Kenya, and Malawi), health impact would be reduced, but this effect becomes less substantial (change of <5%) if 50 million or more doses are available. We did not account for within-country variation in vaccine coverage, and the optimisation was based on a single outcome measure, therefore this study should be used to understand overall trends rather than guide country-specific allocation.ConclusionsThese results suggest that the impact of constraints in vaccine supply on the public health impact of the RTS,S malaria vaccine could be reduced by introducing the vaccine at the sub-national level and prioritising countries with the highest malaria incidence.
| S-EPMC7703928 | biostudies-literature
Project description:The WHO called for the elimination of maternal-to-child transmission (MTCT) of HIV and syphilis, a harmonised approach for the improvement of health outcomes for mothers and children. Testing early in pregnancy, treating seropositive pregnant women and preventing syphilis reinfection can prevent MTCT of HIV and syphilis. We assessed the health and economic outcomes of a dual testing strategy in a simulated cohort of 100?000 antenatal care patients in Malawi.We compared four screening algorithms: (1) HIV rapid test only, (2) dual HIV and syphilis rapid tests, (3) single rapid tests for HIV and syphilis and (4) HIV rapid and syphilis laboratory tests. We calculated the expected number of adverse pregnancy outcomes, the expected costs and the expected newborn disability-adjusted life years (DALYs) for each screening algorithm. The estimated costs and DALYs for each screening algorithm were assessed from a societal perspective using Markov progression models. Additionally, we conducted a Monte Carlo multiway sensitivity analysis, allowing for ranges of inputs.Our cohort decision model predicted the lowest number of adverse pregnancy outcomes in the dual HIV and syphilis rapid test strategy. Additionally, from the societal perspective, the costs of prevention and care using a dual HIV and syphilis rapid testing strategy was both the least costly ($226.92 per pregnancy) and resulted in the fewest DALYs (116?639) per 100?000 pregnancies. In the Monte Carlo simulation the dual HIV and syphilis algorithm was always cost saving and almost always reduced DALYs compared with HIV testing alone.The results of the cost-effectiveness analysis showed that a dual HIV and syphilis test was cost saving compared with all other screening strategies. Updating existing prevention of mother-to-child HIV transmission programmes in Malawi and similar countries to include dual rapid testing for HIV and syphilis is likely to be advantageous.
| S-EPMC4956558 | biostudies-literature
Project description:The existence of excess zeros in the distribution of antenatal care (ANC) visits in Bangladesh raises the research question of whether there are two separate generating processes in taking ANC and the frequency of ANC. Thus the main objective of this study is to identify a proper count regression model for the number of ANC visits by pregnant women in Bangladesh covering the issues of overdispersion, zero-inflation, and intra-cluster correlation with an additional objective of determining risk factors for ANC use and its frequency. The data have been extracted from the nationally representative 2014 Bangladesh Demographic and Health Survey, where 22% of the total 4493 women did not take any ANC during pregnancy. Since these zero ANC visits can be either structural or sampling zeros, two-part zero-inflated and hurdle regression models are investigated along with the standard one-part count regression models. Correlation among response values has been accounted for by incorporating cluster-specific random effects in the models. The hurdle negative binomial regression model with cluster-specific random intercepts in both the zero and the count part is found to be the best model according to various diagnostic tools including likelihood ratio and uniformity tests. The results show that women who have poor education, live in poor households, have less access to mass media, or belong to the Sylhet and Chittagong regions are less likely to use ANC and also have fewer ANC visits. Additionally, women who live in rural areas, depend on family members' decisions to take health care, and have unintended pregnancies had fewer ANC visits. The findings recommend taking both cluster-specific random effects and overdispersion and zero-inflation into account in modelling the ANC data of Bangladesh. Moreover, safe motherhood programmes still need to pay particular attention to disadvantaged and vulnerable subgroups of women.
| S-EPMC6980537 | biostudies-literature
Project description:ObjectiveTo examine the performances of an alternative strategy to decide initiating BP-lowering drugs called Proportional Benefit (PB). It selects candidates addressing the inequity induced by the high-risk approach since it distributes the gains proportionally to the burden of disease by genders and ages.Study design and settingMild hypertensives from a Realistic Virtual Population by genders and 10-year age classes (range 35-64 years) received simulated treatment over 10 years according to the PB strategy or the 2007 ESH/ESC guidelines (ESH/ESC). Primary outcomes were the relative life-year gain (life-years gained-to-years of potential life lost ratio) and the number needed to treat to gain a life-year. A sensitivity analysis was performed to assess the impact of changes introduced by the ESH/ESC guidelines appeared in 2013 on these outcomes.ResultsThe 2007 ESH/ESC relative life-year gains by ages were 2%; 10%; 14% in men, and 0%; 2%; 11% in women, this gradient being abolished by the PB (relative gain in all categories = 10%), while preserving the same overall gain in life-years. The redistribution of benefits improved the profile of residual events in younger individuals compared to the 2007 ESH/ESC guidelines. The PB strategy was more efficient (NNT = 131) than the 2013 ESH/ESC guidelines, whatever the level of evidence of the scenario adopted (NNT = 139 and NNT = 179 with the evidence-based scenario and the opinion-based scenario, respectively), although the 2007 ESH/ESC guidelines remained the most efficient strategy (NNT = 114).ConclusionThe Proportional Benefit strategy provides the first response ever proposed against the inequity of resource use when treating highest risk people. It occupies an intermediate position with regards to the efficiency expected from the application of historical and current ESH/ESC hypertension guidelines. Our approach allows adapting recommendations to the risk and resources of a particular country.
| S-EPMC4631497 | biostudies-literature
Project description:OBJECTIVES:To identify the determinants of antenatal care (ANC) utilisation in sub-Saharan Africa. DESIGN:Systematic review. DATA SOURCES:Databases searched were PubMed, OVID, EMBASE, CINAHL and Web of Science. ELIGIBILITY CRITERIA:Primary studies reporting on determinants of ANC utilisation following multivariate analysis, conducted in sub-Saharan Africa and published in English language between 2008 and 2018. DATA EXTRACTION AND SYNTHESIS:A data extraction form was used to extract the following information: name of first author, year of publication, study location, study design, study subjects, sample size and determinants. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist for reporting a systematic review or meta-analysis protocol was used to guide the screening and eligibility of the studies. The Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies was used to assess the quality of the studies while the Andersen framework was used to report findings. RESULTS:74 studies that met the inclusion criteria were fully assessed. Most studies identified socioeconomic status, urban residence, older/increasing age, low parity, being educated and having an educated partner, being employed, being married and Christian religion as predictors of ANC attendance and timeliness. Awareness of danger signs, timing and adequate number of antenatal visits, exposure to mass media and good attitude towards ANC utilisation made attendance and initiation of ANC in first trimester more likely. Having an unplanned pregnancy, previous pregnancy complications, poor autonomy, lack of husband's support, increased distance to health facility, not having health insurance and high cost of services negatively impacted the overall uptake, timing and frequency of antenatal visits. CONCLUSION:A variety of predisposing, enabling and need factors affect ANC utilisation in sub-Saharan Africa. Intersectoral collaboration to promote female education and empowerment, improve geographical access and strengthened implementation of ANC policies with active community participation are recommended.
| S-EPMC6797296 | biostudies-other
Project description:In malaria-endemic areas, Plasmodium falciparum prevalence is often high in young women because of 1) low use of insecticide-treated nets before their first pregnancy and 2) acquired immunity, meaning infections are asymptomatic and thus untreated. Consequently, a common source of malaria in pregnancy (MiP) may be infected women becoming pregnant, rather than pregnant women becoming infected. In this study, prevalence of infection was determined by microscopy at first antenatal care (ANC) visit in primigravidae and secundigravidae in Ghana, Burkina Faso, Mali, and The Gambia, four countries with strong seasonal variations in transmission. Duration of pregnancy spent in the rainy season and other risk factors for infection were evaluated using multivariable Poisson regression. We found that the overall prevalence of malaria at first ANC was generally high and increased with time spent pregnant during the rainy season: prevalence among those with the longest exposure was 59.7% in Ghana, 56.7% in Burkina Faso, 42.2% in Mali, and 16.8% in Gambia. However, the prevalence was substantial even among women whose entire pregnancy before first ANC had occurred in the dry season: 41.3%, 34.4%, 11.5%, and 7.8%, respectively, in the four countries. In multivariable analysis, risk of infection was also higher among primigravidae, younger women, and those of lower socioeconomic status, independent of seasonality. High prevalence among women without exposure to high transmission during their pregnancy suggests that part of the MiP burden results from long-duration infections, including those acquired preconception. Prevention of malaria before pregnancy is needed to reduce the MiP burden.
| S-EPMC5929207 | biostudies-literature
Project description:BACKGROUND:Undernutrition among children under 5 years of age continues to be a public health challenge in many low- and middle-income countries and can lead to growth stunting. Infectious diseases may also affect child growth, however their actual impact on the latter can be difficult to quantify. In this paper, we analyse data from 20 Demographic and Health Surveys (DHS) conducted in 13 African countries to investigate the relationship between malaria and stunting. Our objective is to make inference on the association between malaria incidence during the first year of life and height-for-age Z-scores (HAZs). METHODS:We develop a geostatistical model for HAZs as a function of both measured and unmeasured child-specific and spatial risk factors. We visualize stunting risk in each of the 20 analysed surveys by mapping the predictive probability that HAZ is below - 2. Finally, we carry out a meta-analysis by modelling the estimated effects of malaria incidence on HAZ from each DHS as a linear regression on national development indicators from the World Bank. RESULTS:A non-spatial univariate linear regression of HAZ on malaria incidence showed a negative association in 18 out of 20 surveys. However, after adjusting for spatial risk factors and controlling for confounding effects, we found a weaker association between HAZ and malaria, with a mix of positive and negative estimates, of which 3 out of 20 are significantly different from zero at the conventional 5% level. The meta-analysis showed that this variation in the estimated effect of malaria incidence on HAZ is significantly associated with the amount of arable land. CONCLUSION:Confounding effects on the association between malaria and stunting vary both by country and over time. Geostatistical analysis provides a useful framework that allows to account for unmeasured spatial confounders. Establishing whether the association between malaria and stunting is causal would require longitudinal follow-up data on individual children.
| S-EPMC5828493 | biostudies-literature
Project description:ObjectivesHigh-quality evidence of effectiveness and cost-effectiveness is rarely available and relevant for health policy decisions in low-resource settings. In such situations, innovative approaches are needed to generate locally relevant evidence. This study aims to inform decision-making on antenatal care (ANC) recommendations in Rwanda by estimating the incremental cost-effectiveness of the recent (2016) WHO antenatal care recommendations compared to current practice in Rwanda.MethodsTwo health outcome scenarios (optimistic, pessimistic) in terms of expected maternal and perinatal mortality reduction were constructed using expert elicitation with gynaecologists/obstetricians currently practicing in Rwanda. Three costing scenarios were constructed from the societal perspective over a 1-year period. The two main inputs to the cost analyses were a Monte Carlo simulation of the distribution of ANC attendance for a hypothetical cohort of 373,679 women and unit cost estimation of the new recommendations using data from a recent primary costing study of current ANC practice in Rwanda. Results were reported in 2015 USD and compared with the 2015 Rwandan per-capita gross domestic product (US$ 697).ResultsIncremental health gains were estimated as 162,509 life-years saved (LYS) in the optimistic scenario and 65,366 LYS in the pessimistic scenario. Incremental cost ranged between $5.8 and $11 million (an increase of 42% and 79%, respectively, compared to current practice) across the costing scenarios. In the optimistic outcome scenario, incremental cost per LYS ranged between $36 (for low ANC attendance) and $67 (high ANC attendance), while in the pessimistic outcome scenario, it ranged between $90 (low ANC attendance) and $168 (high ANC attendance) per LYS. Incremental cost effectiveness was below the GDP-based thresholds in all six scenarios.DiscussionImplementing the new WHO ANC recommendations in Rwanda would likely be very cost-effective; however, the additional resource requirements are substantial. This study demonstrates how expert elicitation combined with other data can provide an affordable source of locally relevant evidence for health policy decisions in low-resource settings.
| S-EPMC6451275 | biostudies-literature
Project description:BackgroundEvidence of the association between early antenatal care (ANC) and receiving at least three doses of sulphadoxine-pyrimethamine (IPTp3+) during pregnancy is limited. It's also unclear whether the association between early ANC and IPTp3+ is modified by planned pregnancy status.ObjectivesOur primary aim was to assess the relationship between early ANC and IPTp3+ and to assess whether this relationship is modified by a woman's planned pregnancy status. We also estimated IPTp3+ coverage across Sub-Saharan African countries.MethodsData on 77 183 mothers with a live birth in the past two years were analyzed using multiple indicator cluster surveys (MICSs) from 17 Sub-Saharan African countries conducted between 2013 and 2019. We used modified Poisson regression with a robust variance to assess the association between early ANC and IPTp3+, while adjusting for country, clustering, stratification and sample weights. Effect modification by planned pregnancy status was assessed on the additive and multiplicative scales. We used meta-analytic techniques to pool prevalent estimates of IPTp3+ across all countries.FindingsIPTp3+ overall coverage was 22.1% (95% CI: 17.0%, 27.1%), and ranged from 2.9% (95% CI: 1.3%, 4.4%) in São Tomé and Príncipe to 51.7% (95% CI: 49.2%, 54.1%) in Ghana. IPTp3+ coverage was 30% higher among mothers who had early ANC compared to those who did not have early ANC [adjusted prevalence ratio (aPR): 1.30, 95% CI: 1.23,1.36]. There was evidence of effect modification on the additive [relative excess risk due to interaction (RERI): 0.08, 95% CI: 0.0002, 0.15] and multiplicative (aPR: 1.10, 95% CI: 1.01, 1.20) scales.ConclusionsIPTp3+ coverage was low across many of the countries in Sub-Saharan Africa. Women who had early ANC were more likely to receive IPTp3+. Women whose pregnancies were unplanned were less likely to receive IPTp3+, but our effect modification analysis showed that early ANC among such women can increase IPTp3+ coverage.
| S-EPMC8757383 | biostudies-literature