ONGOING STUDY:
GASTROSAM

GASTROSAM PROJECT

Research Details

Detailed study information

Full study title

Gastroenteritis Rehydration of Children with Severe Acute Malnutrition (GASTROSAM): A Phase II Randomised Controlled Trial

Study overview

Children admitted to hospital with severe acute malnutrition frequently have diarrhoea and dehydration. Historically, international guidelines have recommended cautious oral rehydration using ReSoMal, a low-sodium solution developed for malnourished children. Intravenous fluids have generally been restricted to children with shock because of concerns about heart failure, sodium imbalance and fluid overload.

However, these recommendations were based largely on expert opinion rather than robust clinical trial evidence. GASTROSAM was designed to establish whether alternative oral and intravenous rehydration strategies could be administered safely to children with severe acute malnutrition.

Study objectives

The study aimed to:

  • Compare oral and intravenous rehydration strategies in children with severe acute malnutrition and gastroenteritis.
  • Determine whether rapid or slow intravenous rehydration could be administered safely.
  • Compare standard low-osmolarity WHO oral rehydration solution with ReSoMal.
  • Assess mortality, electrolyte disturbances, urine output and other indicators of treatment safety.
  • Provide evidence to inform international guidelines for managing dehydration in severely malnourished children.

Study design

GASTROSAM was a Phase II, open-label, randomised controlled trial with a partial factorial design.

Children were placed into two groups according to the severity of dehydration:

  • Stratum A: Children with severe dehydration.
  • Stratum B: Children with moderate or some dehydration.

Children with severe dehydration were randomised to different intravenous or oral rehydration strategies. Children in both strata also participated in the comparison between standard WHO oral rehydration solution and ReSoMal.

The study enrolled 415 children between 2 September 2019 and 27 October 2024. Of these, 272 had severe dehydration and 143 had moderate dehydration. Participants were followed for 28 days. PubMed

Study population

Participants were children who:

  • Were aged between 6 months and 12 years.
  • Had severe acute malnutrition.
  • Were admitted to hospital with diarrhoea.
  • Had clinical signs of moderate or severe dehydration.

Study locations

The trial was conducted at six hospitals across:

  • Uganda
  • Kenya
  • Niger
  • Nigeria

The Ugandan study sites were:

  • Mbale Regional Referral Hospital
  • Soroti Regional Referral Hospital

The original East African phase also included Kilifi County Hospital in Kenya. UCL Innovative Clinical Trials Unit

Interventions

Intravenous rehydration comparison

Children with severe dehydration were allocated to one of three strategies:

  1. Rapid intravenous rehydration: Ringer’s lactate at 100 ml/kg over three to six hours, with additional fluid boluses permitted for shock.
  2. Slow intravenous rehydration: Ringer’s lactate at 100 ml/kg over eight hours without additional boluses.
  3. Oral or nasogastric rehydration: Rehydration according to the standard approach for children with severe acute malnutrition, with intravenous fluids reserved for shock.

Oral rehydration comparison

Children were also randomly allocated to receive either:

  • Standard low-osmolarity WHO oral rehydration solution; or
  • ReSoMal, the low-sodium rehydration solution recommended for children with severe acute malnutrition.

Main outcomes assessed

The trial assessed:

  • Mortality at 96 hours and 28 days.
  • Changes in blood sodium concentration.
  • Urine output.
  • Development of shock.
  • Vomiting and requirement for nasogastric administration.
  • Pulmonary oedema, heart failure or other evidence of fluid overload.
  • Electrolyte disturbances, including hyponatraemia and hypokalaemia.
  • Serious adverse events and the general feasibility of each strategy.

Key findings

Intravenous rehydration findings

Among the 272 children with severe dehydration, mortality at 96 hours was similar between intravenous and oral rehydration:

  • 9 children, or 7%, died in the combined intravenous groups.
  • 11 children, or 8%, died in the oral rehydration group.

No cases of pulmonary oedema or heart failure were observed. Intravenous rehydration corrected low sodium levels more quickly, although careful monitoring of potassium remained important. The findings indicated that both rapid and slow intravenous rehydration could be safely administered under close clinical supervision. New England Journal of Medicine

Oral rehydration findings

The increase in blood sodium concentration after 24 hours was similar in children receiving standard WHO oral rehydration solution and those receiving ReSoMal.

There was also no statistically significant difference in mortality by day 28:

  • 19 children, or 9%, died in the WHO-ORS group.
  • 24 children, or 12%, died in the ReSoMal group.

No fluid-overload events were observed in either group. These findings suggest that standard WHO oral rehydration solution is a safe alternative to ReSoMal for children with severe acute malnutrition and dehydration. The Lancet Child & Adolescent Health study abstract

Importance of the study

GASTROSAM challenges the long-standing assumption that children with severe acute malnutrition cannot safely receive standard intravenous or oral rehydration treatments.

The results could help simplify treatment guidelines by reducing unnecessary differences between rehydration protocols for malnourished and non-malnourished children. This is particularly important in hospitals where ReSoMal may not always be available and where complicated rehydration protocols can be difficult to implement.

The findings also emphasise that rehydration should be accompanied by close monitoring of vital signs, electrolyte levels and clinical deterioration.

Study leadership and collaborators

The study’s Chief Investigator was Professor Kathryn Maitland, Trial Manager: Ayub Mpoya and the country Principal Investigator was Professor Peter Olupot-Olupot of Mbale Clinical Research Institute

The international research collaboration included:

  • Mbale Clinical Research Institute
  • Mbale Regional Referral Hospital
  • Soroti Regional Referral Hospital
  • Imperial College London
  • MRC Clinical Trials Unit at University College London
  • KEMRI–Wellcome Trust Research Programme
  • Médecins Sans Frontières
  • Participating hospitals in Kenya, Niger and Nigeria

Imperial College London was the study sponsor, while the MRC Clinical Trials Unit at UCL provided trial coordination and statistical expertise.

Funding

GASTROSAM was funded through the Joint Global Health Trials Scheme involving:

  • UK Medical Research Council
  • UK Department for International Development
  • Wellcome
  • Médecins Sans Frontières

The principal grant number was MR/R018502/1. UCL trial report

Ethics and trial registration

Ugandan regulatory approvals included:

  • Mbale Regional Referral Hospital Research Ethics Committee: MRRHREC OUT-107/2018
  • Uganda National Council for Science and Technology: HS 2559
  • National Drug Authority: CTC 0172-2021

The study was prospectively registered as:

  • ISRCTN: ISRCTN76149273
  • Pan-African Clinical Trials Registry: PACTR202103852542919

Study status

Completed

Participant recruitment ended on 27 October 2024. The principal intravenous rehydration results were published in 2025, and the oral rehydration findings were published in 2026.

Selected publications

  1. Olupot-Olupot P, Aloroker F, Mpoya A, et al. Gastroenteritis Rehydration of Children with Severe Acute Malnutrition (GASTROSAM): A Phase II Randomised Controlled Trial—Trial Protocol. Wellcome Open Research. 2021;6:160. Read the protocol
  2. Maitland K, Ouattara SM, Sainna H, et al. Intravenous Rehydration for Severe Acute Malnutrition with Gastroenteritis. New England Journal of Medicine. 2025;393:1257–1268. Read the publication
  3. Maitland K, et al. Oral Rehydration for Severe Malnutrition in Children with Moderate and Severe Dehydration (GASTROSAM): A Phase 2, Open-Label, Superiority Randomised Controlled Trial. The Lancet Child & Adolescent Health. 2026;10(5):319–329. Read the abstract

Study Summary

Senior Fellow
Prof. Peter Olupot-Olupot
MB.ChB, MPH, PhD, SRF, FUNAS, FRCP

Sponsor: Imperial College London

REC Approval #: MRRHREC OUT- 107/2018

UNCST Approval #: HS 2559

NDA Approval #: CTC 0172-2021

Study Duration: 24 months

Sites in Uganda: Soroti RRH and Mbale RRH in Uganda, Kilifi county hospital in Kenya

Population: Children aged 6month – 12 years with severe malaria

Sample size: 200 children

Study Design: Open phase II trial with factorial design.

About

Ms. Adyango Catherine is a Human Resource Manager and Senior Grants Professional with over 15 years of experience in managing multimillion-dollar donor portfolios, project operations, and organizational systems strengthening. She currently serves as Human resource Manager at Mbale Clinical Research Institute (MCRI), where she leads in Human resource management,  donor compliance, project operations, and institutional capacity building.

At MCRI, Catherine has combined her expertise in grant management and human resources to establish efficient systems that support both research and staff welfare. She played a pivotal role in championing organizational culture reforms, developing HR policies, strengthening staff welfare schemes, and promoting inclusive recruitment processes. She also streamlined adoption of a Human Resource Management Information System (HRMIS/ESS), which reduced administrative bottlenecks and improved efficiency across teams.

Her academic background includes a Postgraduate Diploma in Human Resource Management (Uganda Management Institute), an MSc in Health Services Management, and a bachelor’s degree in business administration & management. Catherine is also pursuing ACCA training, demonstrating her commitment to continuous professional growth.

Catherine’s career reflects a strong commitment to strategic leadership, staff development, and inclusive programming, with a proven ability to balance donor expectations and human resource needs. Her work at MCRI has significantly contributed to building sustainable research capacity, enhancing compliance systems, and creating a supportive work environment that empowers both researchers and administrative staff.

About

Denis Amorut serves as the Study Site Coordinator at the Mbale Clinical Research Institute’s Soroti Site. He is a qualified Registered Nurse with a Bachelor of Science in Health Services Management from the Islamic University in Uganda and a Diploma in Comprehensive Nursing from Soroti School of Registered Comprehensive Nursing. Additionally, he is currently pursuing an Advanced Postgraduate Diploma in Clinical Research & Quality Assurance at James Lind Institute, showcasing his commitment to advancing his expertise in clinical research. Denis has an extensive professional background with 12 years in clinical nursing practice and 11 years dedicated to clinical research. He is registered with the Uganda Midwives and Nurses Council, highlighting his professional standing in the healthcare sector.
 
Throughout his career, Denis has held significant positions such as Trial Manager since November 2021 and previously as Study Site Coordinator at Soroti Regional Referral and Teaching Hospital from 2008 to October 2021. He also serves as a member of the Medicine and Therapeutic Committee at the same hospital since 2018. Denis has enriched his knowledge and skills through numerous online courses and certifications in areas like research ethics, data management for clinical studies, Good Clinical Practice (GCP), and managing health emergencies like Covid-19. His involvement in various research studies, including the TRACT study, and his roles in hospital committees further demonstrate his dedication to both practice and research in healthcare, focusing on improving patient care through evidence-based practices.

About

Ms. Linda Isabirye serves as the Public and Community Engagement Officer at MCRI, where her role encompasses a variety of tasks aimed at enhancing the Institute’s interaction with both internal and external communities. Her work is divided into two primary focuses: public engagement, where she communicates the Institute’s research and ideas to the public, and community engagement, where she assists others in conducting research and achieving their objectives.

In her community engagement efforts, Linda is involved in developing and sustaining a public engagement and involvement framework for the research program. She identifies local opportunities for community collaboration, nurturing relationships with MCRI’s research scientists, staff, and the broader community.

With over two years of experience, she has worked extensively with diverse community stakeholders. Her responsibilities include coordinating activities for the Community Advisory Board (CAB), designing, and overseeing the execution of Community Engagement (CE) initiatives. These initiatives are crucial for identifying, recruiting, and retaining volunteers, engaging community leadership, and supporting the formation and operation of community peer groups. This includes working with study participants, family support groups, and youth and adolescent groups, among others.

About

Rita Muhindo holds a MSc. Molecular Biology from Staffordshire University, UK. She attained her BSc. Biomedical Laboratory Science and Technology degree from Makerere University and an Advanced Diploma in Health Services Management from Islamic University in Uganda. She joined Mbale Clinical Research Institute in July 2011 as a laboratory technologist participating in setting up various laboratory assays for all clinical trials at the MCRI.

She is currently the laboratory manager of MCRI, a role which involves supervision all laboratory research activities at MCRI main and satellite laboratories. She has over twelve years of experience in managing laboratory clinical research and diagnostics service delivery across several key disciplines including molecular, immunology, hematology, microbiology and clinical chemistry.

She has keen interest in understanding the prevalence of red cell polymorphisms present in Ugandan donor populations. Her main focus of her MSc project was on the prevalence of Glucose-6-Phosphate dehydrogenase deficiency, α-thalassaemia and Haemoglobin S among Ugandan donors. Rita is also keen to explore the effects of these polymorphisms on the resolution of severe anaemia.

About

Dr. Charles Benard Okalebo is a highly qualified professional with a B. Pharm, an MPH, and currently a fellow in Infectious Disease and Field Epidemiology under the EDCTP-funded IDEA fellowship. His background as a pharmacist and public health specialist, combined with his role as a Quality Assurance Officer, has provided him with extensive experience in clinical research. This diverse training has honed his skills in assessing healthcare gaps, identifying problems, and designing projects to address these deficiencies. Dr. Okalebo values accuracy, integrity, quality, and career growth above all.
 
He is an experienced and determined professional in conducting clinical trials for both infectious and non-infectious diseases. With eight years in the research field, he has served as a Pharmacist and Quality Assurance Officer at the Mbale Clinical Research Institute, focusing on various types of clinical trials related to infectious diseases. His involvement spans across all phases of clinical trials (I-III), including protocol design, review, and implementation; navigating regulatory approval processes; managing investigational medicinal products (IMP); monitoring studies; establishing and implementing Quality Management processes; pharmacovigilance; and leading training sessions on the ethical conduct of research. The trials he has participated in include TRACT (ISRCTN84086586), GASTROSAM (ISRCTN76149273), PAC (ISRCTN11594437), FLACSAM (ISRCTN18051843), MIMBLE (ISRCTN10309022), and TABS (ISRCTN49726849) studies.
 
Dr. Okalebo is a dedicated researcher with a keen interest in advancing his career in pharmaco-epidemiology, statistics, and pharmacovigilance.

About

Felix Opio joined the Mbale Clinical Research Institute (MCRI) in April 2014 as Data Manager under the REACH (Realizing Effectiveness Across Continents with Hydroxyurea) ClinicalTrials.gov NCT01966731) which is a prospective, Phase I/II open-label trial of hydroxyurea designed to evaluate the feasibility, safety, long-term risks and benefits of hydroxyurea treatment for children with SCA in four sub-Saharan African countries (Mable Uganda,Kilifi Kenya, Luanda Angola and Kinshasa DRC).

He holds a Bachelor of Science in Computer Science from Gulu University, a post graduate diploma in Monitoring and Evaluation from Uganda Management Institute (UMI), Certificate in Project Management Professional from Devimpact Institute Kenya and various other certification in Clinical database development.

He Has 9 years of experience in Clinical Database design and Management, He is Currently overseeing data management work for the REACH study and all the day to day activities of the Project, He is also a member of the internal Clinical Trial Monitoring Unit and A chairperson Procurement Committee for Mbale Clinical Research Institute.

About

Ebitu Caleb Daniel serves as an I.T Support Officer at the Mbale Clinical Research Institute. He is recognized as an accomplished network and systems administrator, who takes pleasure in applying his skills to support and contribute to the technological advancement of research within the institution.
 
Ebitu graduated from Uganda Christian University Mukono with a Bachelor’s degree in Computer Science. Over the years, he has also acquired various certifications including CCNA, Information Security, Google Cloud Developer, PMP (Telecom), and Federated Identity Management.

About

Laban has accumulated over four years of experience in managing research financial processes since joining the Mbale Clinical Research Institute on July 1, 2019, as an Accounts Assistant. This experience complements his extensive background of over ten years in the banking sector, where he has previously worked for two banks in roles involving people management, cash management, internal controls, and accountability.

He holds a Bachelor’s degree in Business Studies, specializing in Accounting, from the Islamic University of Uganda. He is currently pursuing a Certificate of Public Accountants (CPA) from the Institute of Certified Public Accountants of Uganda (ICPAU), with only two papers remaining to complete the course.

Driven by an ambition to advance his career in accounting and expand his experience in research-related accounting managed by well-established systems and processes, he believes that MCRI is the ideal place for his professional growth.