GEMS1A Case Control

Related studies:

GEMS1A HUAS Lite Survey: Two community-based Healthcare Services Utilization and Attitudes Surveys conducted in conjunction with the GEMS1A case control study.
GEMS1 Case Control is the case control study preceding this follow-on study.
GEMS1 HUAS/HUAS Lite Survey: Three community-based Healthcare Services Utilization and Attitudes Surveys conducted in conjunction with the GEMS1 case control study.

Background: The Global Enteric Multicenter Study (GEMS) was a prospective, age-stratified, matched case-control study of the burden, etiology, and adverse clinical outcomes of diarrheal diseases among children aged 0-59 months seeking care at health care facilities during a 36-month period at seven sites in sub-Saharan Africa and South Asia. GEMS1 aimed to elucidate the more clinically severe medically-attended diarrheal episodes to guide and prioritize efforts to prevent the most life-threatening and disabling illnesses. It is also important to characterize the "less severe" diarrhea (LSD) episodes for which care is sought at health care facilities, recognizing that even though there may be fewer adverse health consequences from these illnesses, the overall LSD burden could be greater because it is more common than "moderate-to-severe" diarrhea (MSD). Whether there are meaningful differences in the distribution of etiologies of LSD compared with MSD also must be understood to optimize diarrheal disease prevention and treatment. Therefore a one-year follow-on study designated GEMS-1A was conducted in which six GEMS sites performed simultaneous case-control studies of both MSD and LSD, and one GEMS site performed a case-control study of MSD only. At the time of these studies, no site had introduced rotavirus vaccine into its Expanded Program on Immunization for young infants.

Objectives: The objective of GEMS-1A was to determine whether the findings of GEMS were generalizable to episodes of less-severe diarrhoea (LSD), which represent the majority of paediatric diarrhea in patients presenting to health-care centres. This study was designed to simultaneously examine MSD and LSD.

The primary outcomes of the GEMS-1A study were to characterize, for LSD in addition to MSD, the overall and pathogen-specific population-based attributable incidence and the pathogen-specific attributable fraction, and to assess the frequency of nutritional faltering and other adverse clinical consequences among children with these two diarrheal syndromes relative to the control population. The outcomes were assessed by site and age stratum, and across all sites for incidence and nutritional outcomes.

Methodology:

Study Sites: Seven GEMS sites with moderate-to-high under-five child mortality participated in GEMS-1A- four in Africa (Bamako, Mali; Manhiça, Mozambique; Basse, The Gambia; and Nyanza Province, Kenya) and three in Asia (Mirzapur, Bangladesh; Kolkata, India; and Bin Qasim Town, Karachi, Pakistan).

Dates of Data Collection: October 2011- January 2013

Study Design: Case-Control study

Eligibility Criteria: Participants at each site belonged to a censused population serially updated for births, deaths, and migrations using a demographic surveillance system (DSS). For case enrollment, sites selected sentinel hospitals or health centers (SHCs) where DSS children sought care for diarrheal illnesses.

Cases: All children aged 0-59 months belonging to the DSS population at each site who sought care at a SHC during a 12-month period were screened for diarrhea (>3 loose stools during the previous 24 hours). Episodes eligible for inclusion as MSD were new (onset after >7 diarrhea-free days), acute (onset within the previous 7 days), and satisfied at least one of the following criteria for MSD:

Sunken eyes (confirmed by parent/caretaker as more than normal)
Loss of skin turgor (abdominal skin pinch with slow [even a brief instant] or very slow [>2 seconds] recoil)
Intravenous hydration administered or prescribed
Dysentery (visible blood in loose stools)
Hospitalized

The remaining new and acute diarrhea episodes were considered LSD. Note, in Kenya, almost no LSD cases presented to health centers, so LSD cases were not recruited.

Controls: For each case of MSD or LSD enrolled, we enrolled 1-3 community control children without diarrhea in the last 7 days, randomly selected from the site's DSS database within 14 days of the case. Controls were matched to each individual case by age, gender, and residence (same or nearby village or neighborhood as the case).

Data Collection: At enrollment, parents/primary caretakers of cases and controls underwent standardized interviews to solicit demographic, epidemiologic, and clinical information. GEMS staff measured the child's length/height. Medical management by clinicians at the SHC and clinical condition upon discharge were documented. A single follow-up home visit was performed ~60 days after enrollment to assess the child's vital status and repeat anthropometric measurements. At enrollment, each case and control provided fresh stool that was placed in cold storage and transport media according to the protocol. If antibiotics were to be administered to cases before stool was produced, two rectal swabs were obtained for bacterial culture pending passage of the whole stool for the remaining assays. With few exceptions, GEMS-1A utilized the same clinical/epidemiologic, microbiologic, data management, and analytic methods described for the GEMS1 36-month study of MSD alone.

Study Documentation:

CRF 02 - Registration log for cases
CRF 03 - Eligibility for cases
CRF 04A - Enrollment for cases - non-medical
CRF 04B - Enrollment for cases - medical
CRF 05 - 60 day follow-up for cases & controls
CRF 06 - Eligibility for controls
CRF 07 - Enrollment questionnaire for controls
CRF 09 - Memory aid score sheet
CRF 11 - Stool collection
CRF 15 - Stool accession
CRF 16 - Stool culture
CRF 17 - E. coli polymerase chain reaction
CRF 17A - EPEC polymerase chain reaction
CRF 18 - Protozoal and viral immunoassays
CRF 19 - RT-PCR for viruses
All CRFs - Download all CRFs as PDFs in .zip format

ClinEpiDB Data Integration: Data files were provided to ClinEpiDB as flat, csv files. These datasets were merged by unique ID and redundant or administrative columns were dropped from presentation on ClinEpiDB.org. All dates were obfuscated per participant through the application of a random number algorithm that shifted dates no more than seven days to comply with the ethical conduct of human subjects research.

Acknowledgements: We thank the families who participated in these studies and the project field and laboratory staff for their professionalism and dedication.

Financial Support: The GEMS-1 and GEMS-1A work was supported by grants from the Bill & Melinda Gates Foundation.

Ethics Statement: The study protocol was approved by ethics committees at the University of Maryland, Baltimore and at each field site. Parents/caregivers of participants provided written informed consent, and a witnessed consent was obtained for illiterate parents/caretakers in their local language.

Last updated: May 14, 2021

Contact:
Gates Enterics Project

Center for Vaccine Development

University of Maryland, Baltimore

685 W. Baltimore St., Room 480

Baltimore, MD 21201 USA

Phone: [phone]

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The Global Enteric Multi-Center Study (GEMS) was a prospective, multi-center, case-control study of acute diarrhea in children 0-59 months of age. GEMS-1A is a one-year follow-on of GEMS looking at both moderate-to-severe diarrhea and less severe diarrhea cases. Each site recruited cases with diarrhea from hospitals or ambulatory facilities and up to three matched community controls per case. Participants were assessed at enrollment and at a 60-day follow-up visit.