Mapping geographical inequalities in oral rehydration therapy coverage in low-income and middle-income countries, 2000-17

Background: Oral rehydration solution (ORS) is a form of oral rehydration therapy (ORT) for diarrhoea that has the potential to drastically reduce child mortality; yet, according to UNICEF estimates, less than half of children younger than 5 years with diarrhoea in low-income and middle-income countries (LMICs) received ORS in 2016. A variety of recommended home fluids (RHF) exist as alternative forms of ORT; however, it is unclear whether RHF prevent child mortality. Previous studies have shown considerable variation between countries in ORS and RHF use, but subnational variation is unknown. This study aims to produce high-resolution geospatial estimates of relative and absolute coverage of ORS, RHF, and ORT (use of either ORS or RHF) in LMICs. Methods: We used a Bayesian geostatistical model including 15 spatial covariates and data from 385 household surveys across 94 LMICs to estimate annual proportions of children younger than 5 years of age with diarrhoea who received ORS or RHF (or both) on continuous continent-wide surfaces in 2000-17, and aggregated results to policy-relevant administrative units. Additionally, we analysed geographical inequality in coverage across administrative units and estimated the number of diarrhoeal deaths averted by increased coverage over the study period. Uncertainty in the mean coverage estimates was calculated by taking 250 draws from the posterior joint distribution of the model and creating uncertainty intervals (UIs) with the 2·5th and 97·5th percentiles of those 250 draws. Findings: While ORS use among children with diarrhoea increased in some countries from 2000 to 2017, coverage remained below 50% in the majority (62·6%; 12 417 of 19 823) of second administrative-level units and an estimated 6 519 000 children (95% UI 5 254 000-7 733 000) with diarrhoea were not treated with any form of ORT in 2017. Increases in ORS use corresponded with declines in RHF in many locations, resulting in relatively constant overall ORT coverage from 2000 to 2017. Although ORS was uniformly distributed subnationally in some countries, within-country geographical inequalities persisted in others; 11 countries had at least a 50% difference in one of their units compared with the country mean. Increases in ORS use over time were correlated with declines in RHF use and in diarrhoeal mortality in many locations, and an estimated 52 230 diarrhoeal deaths (36 910-68 860) were averted by scaling up of ORS coverage between 2000 and 2017. Finally, we identified key subnational areas in Colombia, Nigeria, and Sudan as examples of where diarrhoeal mortality remains higher than average, while ORS coverage remains lower than average. Interpretation: To our knowledge, this study is the first to produce and map subnational estimates of ORS, RHF, and ORT coverage and attributable child diarrhoeal deaths across LMICs from 2000 to 2017, allowing for tracking progress over time. Our novel results, combined with detailed subnational estimates of diarrhoeal morbidity and mortality, can support subnational needs assessments aimed at furthering policy makers' understanding of within-country disparities. Over 50 years after the discovery that led to this simple, cheap, and life-saving therapy, large gains in reducing mortality could still be made by reducing geographical inequalities in ORS coverage. This work was primarily supported by a grant from the Bill & Melinda Gates Foundation (OPP1132415). L G Abreu has received support from Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (Finance Code 001), Conselho Nacional de Desenvolvimento Científico e Tecnológico and Fundação de Amparo à Pesquisa do Estado de Minas Gerais. O O Adetokunboh acknowledges the South African Department of Science and Innovation and the National Research Foundation. S M Aljunid acknowledges the Department of Health Policy and Management, Faculty of Public Health, Kuwait University and International Centre for Casemix and Clinical Coding, Faculty of Medicine, National University of Malaysia for the approval and support to participate in this research project. H T Atalay acknowledges Aksum University. M Ausloos and C Herteliu are partially supported by a grant of the Romanian National Authority for Scientific Research and Innovation, CNDS-UEFISCDI, project number PN-III-P4-ID-PCCF-2016-0084. P S Azzopardi was supported by an Australian National Health and Medical Research Council (NHMRC) early career fellowship. A Badawi is supported by the Public Health Agency of Canada. T W Bärnighausen was supported by the Alexander von Humboldt Foundation through the Alexander von Humboldt Professor award, funded by the German Federal Ministry of Education and Research; the EU; the Wellcome Trust; and from National Institute of Child Health and Human Development of National Institutes of Health (NIH; R01-HD084233), National Institute on Aging of NIH (P01-AG041710), National Institute of Allergy and Infectious Diseases of NIH (R01-AI124389 and R01-AI112339), as well as Fogarty International Center of NIH (D43-TW009775). G B Britton is supported by Sistema Nacional de Investigación (SNI) de la Secretaría Nacional de Ciencia, Tecnología e Innovación (SENACYT) of Panamá. A Barac is funded by the Project of Ministry of Education, Science and Technology of the Republic of Serbia (number III45005). D A Bennett was supported by the National Institute for Health Research (NIHR) Oxford Biomedical Research Centre. The views expressed are those of the authors and not necessarily those of the National Health Service, the NIHR, or the UK Department of Health and Social Care. V M Costa acknowledges her grant (SFRH/BHD/110001/2015), received by Portuguese national funds through Fundação para a Ciência e Tecnologia (FCT), IP, under the Norma Transitória DL57/2016/CP1334/CT0006. F Carvalho acknowledges UID/MULTI/04378/2019 and UID/QUI/50006/2019 support with funding from FCT/Ministério da Ciência, Tecnologia e Ensino Superior through national funds. K Deribe is supported by a Wellcome Trust grant (number 201900/Z/16/Z) as part of his International Intermediate Fellowship. C Herteliu is partially supported by a grant co-funded by European Fund for Regional Development through the Operational Program for Competitiveness (project ID P_40_382). P Hoogar thanks Centre for Bio Cultural Studies, Directorate of Research, Manipal Academy of Higher Education, Manipal and Centre for Holistic Development and Research, Kalaghatgi-Karnataka. S M S Islam is funded by a Fellowship from National Heart Foundation of Australia and Deakin University. M Jakovljevic and the Serbian part of this GBD contribution was co-funded through grant OI175014 of the Ministry of Education Science and Technological Development of the Republic of Serbia. A P Kengne is supported by the South African Medical Research Council. Y J Kim's work was supported by the Research Management Centre, Xiamen University Malaysia, grants number XMUMRF/2018-C2/ITCM/0001. K Krishan is supported by a DST PURSE grant and UGC Center of Advanced Study awarded to the Department of Anthropology, Panjab University, Chandigarh, India. M Kumar acknowledges K43 TW010716-03. B Lacey acknowledges support from the NIHR Oxford Biomedical Research Centre and the British Heart Foundation Centre of Research Excellence, Oxford. P T N Memiah acknowledges the Council for the Development of Social Science Research in Africa. M Molokhia is supported by the NIHR Biomedical Research Center at Guy's and St Thomas' National Health Service Foundation Trust and King's College London. I Moreno Velásquez is supported by the Sistema Nacional de Investigación (SENACYT, Panamá). G C Patton is funded by an NHMRC Fellowship. A M Samy received a fellowship from the Egyptian Fulbright Mission programme. M M Santric-Milicevic acknowledges the support of the Ministry of Education, Science and Technological Development of the Republic of Serbia (contract number 175087). A Sheikh acknowledges the support of Health Data Research UK. M R Sobhiyeh acknowledges the Clinical Research Development Center of Imam Reza Hospital, Kermanshah University of Medical Sciences for their wise advice. R Tabarés-Seisdedos was supported in part by grant PI17/00719 from Instituto de Salud Carlos III–FEDER. B Unnikrishnan acknowledges Manipal Academy of Higher Education, Manipal. M R Weaver was supported by the Bill & Melinda Gates Foundation grant OPP1127433. C S Wiysonge was supported by the South African Medical Research Council.