The impact of improved water supply on cholera and diarrhoeal diseases in Uvira, Democratic Republic of the Congo: a protocol for a pragmatic stepped-wedge cluster randomised trial and economic evaluation

Abstract

Introduction Diarrhoeal disease remains a leading cause of mortality and morbidity worldwide. Cholera alone is estimated to cause 95,000 deaths per year, most of which occur in endemic settings with inadequate water access. Whilst a global strategy to eliminate cholera by 2030 calls for investment in improved drinking water services, there is limited rigorous evidence for the impact of improved water supply on endemic cholera transmission in low-income urban settings. Our protocol is designed to deliver a pragmatic health impact evaluation of a large-scale water supply intervention in Uvira (Democratic Republic of the Congo), a cholera transmission hotspot. Methods/design A stepped-wedge cluster randomised trial (SW-CRT) was designed to evaluate the impact of a large-scale drinking water supply intervention on cholera incidence among the 280,000 inhabitants of Uvira. The city was divided into 16 clusters, where new community and household taps will be installed following a randomised sequence over a transition period of up to 8 weeks in each cluster. The primary trial outcomes are the monthly incidence of “confirmed” cholera cases (patients testing positive by rapid detection kit) and of “suspected” cholera cases (patients admitted to the cholera treatment centre). Concurrent process and economic evaluations will provide further information on the context, costs, and efficiency of the intervention. Discussion In this protocol, we describe a pragmatic approach to conducting rigorous research to assess the impacts of a complex water supply intervention on severe diarrhoeal disease and cholera in an unstable, low-resource setting representative of cholera-affected areas. In particular, we discuss a series of pre-identified risks and linked mitigation strategies as well as the value of combining different data collection methods and preparation of multiple analysis scenarios to account for possible deviations from the protocol. The study described here has the potential to provide robust evidence to support more effective cholera control in challenging, high-burden settings. Trial registration This trial is registered on clinicaltrials.gov (NCT02928341, 10th October 2016) and has received ethics approval from the London School of Hygiene and Tropical Medicine (8913, 10603) and from the Ethics Committee from the School of Public Health, University of Kinshasa, Democratic Republic of the Congo (ESP/CE/088/2015).

Effectiveness of case-area targeted interventions including vaccination on the control of epidemic cholera: protocol for a prospective observational study

“…The study will be conducted in a very challenging context—cholera-affected areas of urban or rural and remote areas—where insecurity, poor road access, the rainy season and logistical issues with moving supplies are major concerns. 70 The level of community acceptance of the intervention is dependent on relationships between the community and implementers including MSF and the MOH. Some level of mistrust of government and partners regarding outbreak response are anticipated.…”

Impact on childhood mortality of interventions to improve drinking water, sanitation, and hygiene (WASH) to households: Systematic review and meta-analysis

“…There is also a need for more rigorous studies of water supply improvements. Although prospective evaluations of water supply interventions are being done (e.g., [ 103 ]), we are only aware of one published randomised field trial of a water supply improvement in Ghana [ 104 ] and one study that randomised encouragement of subsidies for household connections in Morocco [ 105 ]. If services are allocated by administrative area or according to a threshold rule (e.g., the share of community members currently covered by a service), it may be possible to use a discontinuity design, an approach that has been shown to generate the same effect estimates as RCTs, when applied prospectively or retrospectively [ 106 ].…”

Impact on childhood mortality of interventions to improve drinking water, sanitation and hygiene (WASH) to households: systematic review and meta-analysis

“…There is also a need for more rigorous studies of water supply improvements. Although prospective evaluations of water supply interventions are being done (e.g., [102]), we are only aware of one published randomised field trial of a water supply improvement in Ghana [103] and one study that randomised encouragement of subsidies for household connections in Morocco [104]. If services are allocated by administrative area or according to a threshold rule (e.g., the share of community members currently covered by a service), it may be possible to use a discontinuity design, an approach that has been shown to generate the same effect estimates as RCTs, whether applied prospectively or retrospectively [105].…”