Drivers of Decline in Diarrhea Mortality Between GEMS and VIDA Studies.

BACKGROUND: Statistical modeling suggests that decreasing diarrhea-associated mortality rates in recent decades are largely attributed to improved case management, rotavirus vaccine, and economic development. METHODS: We examined data collected in 2 multisite population-based diarrhea case-control studies, both conducted in The Gambia, Kenya, and Mali: the Global Enteric Multicenter Study (GEMS; 2008-2011) and Vaccine Impact on Diarrhea in Africa (VIDA; 2015-2018). Population-level diarrhea mortality and risk factor prevalence, estimated using these study data, were used to calculate the attribution of risk factors and interventions for diarrhea mortality using a counterfactual framework. We performed a decomposition of the effects of the changes in exposure to each risk factor between GEMS and VIDA on diarrhea mortality for each site. RESULTS: Diarrhea mortality among children under 5 in our African sites decreased by 65.3% (95% confidence interval [CI]: -80.0%, -45.0%) from GEMS to VIDA. Kenya and Mali had large relative declines in diarrhea mortality between the 2 periods with 85.9% (95% CI: -95.1%, -71.5%) and 78.0% (95% CI: -96.0%, 36.3%) reductions, respectively. Among the risk factors considered, the largest declines in diarrhea mortality between the 2 study periods were attributed to reduction in childhood wasting (27.2%; 95% CI: -39.3%, -16.8%) and an increased rotavirus vaccine coverage (23.1%; 95% CI: -28.4%, -19.4%), zinc for diarrhea treatment (12.1%; 95% CI: -16.0%, -8.9%), and oral rehydration salts (ORS) for diarrhea treatment (10.2%). CONCLUSIONS: The VIDA study sites demonstrated exceptional reduction in diarrhea mortality over the last decade. Site-specific differences highlight an opportunity for implementation science in collaboration with policymakers to improve the equitable coverage of these interventions globally.

Survey-Based Assessment of Water, Sanitation, and Animal-Associated Risk Factors for Moderate-to-Severe Diarrhea in the Vaccine Impact on Diarrhea in Africa (VIDA) Study: The Gambia, Mali, and Kenya, 2015-2018.

BACKGROUND: Pediatric exposures to unsafe sources of water, unsafely managed sanitation, and animals are prevalent in low- and middle-income countries. In the Vaccine Impact on Diarrhea in Africa case-control study, we examined associations between these risk factors and moderate-to-severe diarrhea (MSD) in children <5 years old in The Gambia, Kenya, and Mali. METHODS: We enrolled children <5 years old seeking care for MSD at health centers; age-, sex-, and community-matched controls were enrolled at home. Conditional logistic regression models, adjusted for a priori confounders, were used to evaluate associations between MSD and survey-based assessments of water, sanitation, and animals living in the compound. RESULTS: From 2015 to 2018, 4840 cases and 6213 controls were enrolled. In pan-site analyses, children with drinking water sources below "safely managed" (onsite, continuously accessible sources of good water quality) had 1.5-2.0-fold higher odds of MSD (95% confidence intervals [CIs] ranging from 1.0 to 2.5), driven by rural site results (The Gambia and Kenya). In the urban site (Mali), children whose drinking water source was less available (several hours/day vs all the time) had higher odds of MSD (matched odds ratio [mOR]: 1.4, 95% CI: 1.1, 1.7). Associations between MSD and sanitation were site-specific. Goats were associated with slightly increased odds of MSD in pan-site analyses, whereas associations with cows and fowl varied by site. CONCLUSIONS: Poorer types and availability of drinking water sources were consistently associated with MSD, whereas the impacts of sanitation and household animals were context-specific. The association between MSD and access to safely managed drinking water sources post-rotavirus introduction calls for transformational changes in drinking water services to prevent acute child morbidity from MSD.

Diarrhoeal disease and subsequent risk of death in infants and children residing in low-income and middle-income countries: analysis of the GEMS case-control study and 12-month GEMS-1A follow-on study.

BACKGROUND: The Global Enteric Multicenter Study (GEMS) was a 3-year case-control study that measured the burden, aetiology, and consequences of moderate-to-severe diarrhoea (MSD) in children aged 0-59 months. GEMS-1A, a 12-month follow-on study, comprised two parallel case-control studies, one assessing MSD and the other less-severe diarrhoea (LSD). In this report, we analyse the risk of death with each diarrhoea type and the specific pathogens associated with fatal outcomes. METHODS: GEMS was a prospective, age-stratified, matched case-control study done at seven sites in Africa and Asia. Children aged 0-59 months with MSD seeking care at sentinel health centres were recruited along with one to three randomly selected matched community control children without diarrhoea. In the 12-month GEMS-1A follow-on study, children with LSD and matched controls, in addition to children with MSD and matched controls, were recruited at six of the seven sites; only cases of MSD and controls were enrolled at the seventh site. We compared risk of death during the period between enrolment and one follow-up household visit done about 60 days later (range 50-90 days) in children with MSD and LSD and in their respective controls. Approximately 50 pathogens were detected using, as appropriate, classic bacteriology, immunoassays, gel-based PCR and reverse transcriptase PCR, and quantitative real-time PCR (qPCR). Specimens from a subset of GEMS cases and controls were also tested by a TaqMan Array Card that compartmentalised probe-based qPCR for 32 enteropathogens. FINDINGS: 223 (2·0%) of 11 108 children with MSD and 43 (0·3%) of 16 369 matched controls died between study enrolment and the follow-up visit at about 60 days (hazard ratio [HR] 8·16, 95% CI 5·69-11·68, p<0·0001). 12 (0·4%) of 2962 children with LSD and seven (0·2%) of 4074 matched controls died during the follow-up period (HR 2·78, 95% CI 0·95-8·11, p=0·061). Risk of death was lower in children with dysenteric MSD than in children with non-dysenteric MSD (HR 0·20, 95% CI 0·05-0·87, p=0·032), and lower in children with LSD than in those with non-dysenteric MSD (HR 0·29, 0·14-0·59, p=0·0006). In children younger than 24 months with MSD, infection with typical enteropathogenic Escherichia coli, enterotoxigenic E coli encoding heat-stable toxin, enteroaggregative E coli, Shigella spp (non-dysentery cases), Aeromonas spp, Cryptosporidium spp, and Entamoeba histolytica increased risk of death. Of 61 deaths in children aged 12-59 months with non-dysenteric MSD, 31 occurred among 942 children qPCR-positive for Shigella spp and 30 deaths occurred in 1384 qPCR-negative children (HR 2·2, 95% CI 1·2-3·9, p=0·0090), showing that Shigella was strongly associated with increased risk of death. INTERPRETATION: Risk of death is increased following MSD and, to a lesser extent, LSD. Considering there are approximately three times more cases of LSD than MSD in the population, more deaths are expected among children with LSD than in those with MSD. Because the major attributable LSD-associated and MSD-associated pathogens are the same, implementing vaccines and rapid diagnosis and treatment interventions against these major pathogens are rational investments. FUNDING: Bill & Melinda Gates Foundation.

Household Costs of Diarrhea by Etiology in 7 Countries, The Global Enterics Mulitcenter Study (GEMS).

BACKGROUND: Although there are many overlapping features, pediatric diarrheal diseases can vary in severity, duration, clinical manifestations, and sequelae according to the causal pathogen, which in turn can impact the economic burden on patients and their families. We aimed to evaluate the household costs of diarrheal disease by pathogen in 7 countries. METHODS: We analyzed data from the Global Enteric Multicenter Study (GEMS), a prospective, age-stratified, matched case-control study of moderate to severe diarrheal disease among children aged 0-59 months in 7 low-income countries; 4 in Africa (Kenya, Mali, Mozambique, The Gambia) and 3 in Asia (Bangladesh, India, Pakistan). Demographic, epidemiological, economic, and clinical data were collected, and a stool sample was obtained for microbiological analysis at enrollment. We used a multivariate generalized linear model to assess the effect of rotavirus, Cryptosporidium, heat-stable toxin (ST)-producing enterotoxigenic Escherichia coli (ETEC [ST only or LT plus ST]), Shigella, Campylobacter jejuni, norovirus GII, Vibrio cholerae O1, age, gender, in/outpatient, and country on total costs to the patient/family. RESULTS: Household out-of-pocket costs were higher in Mali than any other country. Within countries, household cost differences between pathogens were minimal and not statistically significantly different. CONCLUSIONS: We found no significant differences in household costs by pathogen. Despite data limitations, understanding pathogen-specific household costs (or lack thereof) is useful, as decision-makers could consider broader illness cost information and its relevance to a particular pathogen's economic burden and contribution to poverty when deciding which pathogens to target for interventions.

The effect of costs on Kenyan households' demand for medical care: why time and distance matter.

In an environment of constrained resources, policymakers must identify solutions for financing and delivering health services that are efficient and sustainable. However, such solutions require that policymakers understand the complex interaction between household utilization patterns, factors influencing household medical decisions, and provider performance. This study examined whether and under what conditions out-of-pocket, transportation, and time costs influenced Kenyan households' choice of medical provider for childhood diarrhoeal illnesses. It compared these decisions with the actual cost and quality of those providers to assess strategies for increasing the utilization of high quality, low-cost primary care. This study analyzed nationally-representative survey data through several multinomial nested logit models. On average, time costs accounted for the greatest share of total costs. Households spent the most time and transportation costs utilizing public care, yet were more likely to incur catastrophic time and out-of-pocket costs seeking private care for their child's diarrhoeal illness. Out-of-pocket, transportation, and time costs influenced households' choice of provider, though demand was cost inelastic and households were most responsive to transportation costs. Poorer households were the most responsive to changes in all cost types and most likely to self-treat or utilize informal care. Many households utilized informal care that, relative to formal care, cost the same but was of worse quality-suggesting that such households were making poor medical decisions for their children. To achieve public policy objectives, such as financial risk protection for childhood illnesses and equitable access to primary care, policymakers could focus on three areas: (1) refine financing strategies for further reducing household out-of-pocket costs; (2) reduce or subsidize time and transportation costs for households seeking public and private care; and (3) increase transparency of costs and quality to improve household decisions.

Global burden of diarrheal diseases among children in developing countries: Incidence, etiology, and insights from new molecular diagnostic techniques.

The Global Enteric Multicenter Study (GEMS) demonstrated that Shigella and enterotoxigenic Escherichia coli (ETEC) producing heat stable toxin (ST) (either alone or in combination with heat labile toxin) are among the most important pathogens associated with moderate-to-severe diarrhea (MSD) in children younger than 5years of age living in developing countries. To inform the design of vaccines and other interventions, we reviewed published data and new results from GEMS characterizing the burden of Shigella and ST-ETEC infections. Clinical parameters were assessed to examine the value of various case definitions as indicators of MSD associated with Shigella and ST-ETEC for use in clinical trials. We discussed advantages and disadvantages of culture-based and culture-independent molecular diagnostics for detecting clinically and epidemiologically relevant disease. Shigella serotyping data from GEMS were examined to identify desirable components of Shigella and ETEC vaccines likely to confer broad protection. These findings can inform the development and implementation of vaccines to prevent these important infections among infants and children in developing countries.

The Burden of Cryptosporidium Diarrheal Disease among Children < 24 Months of Age in Moderate/High Mortality Regions of Sub-Saharan Africa and South Asia, Utilizing Data from the Global Enteric Multicenter Study (GEMS).

BACKGROUND: The importance of Cryptosporidium as a pediatric enteropathogen in developing countries is recognized. METHODS: Data from the Global Enteric Multicenter Study (GEMS), a 3-year, 7-site, case-control study of moderate-to-severe diarrhea (MSD) and GEMS-1A (1-year study of MSD and less-severe diarrhea [LSD]) were analyzed. Stools from 12,110 MSD and 3,174 LSD cases among children aged <60 months and from 21,527 randomly-selected controls matched by age, sex and community were immunoassay-tested for Cryptosporidium. Species of a subset of Cryptosporidium-positive specimens were identified by PCR; GP60 sequencing identified anthroponotic C. parvum. Combined annual Cryptosporidium-attributable diarrhea incidences among children aged <24 months for African and Asian GEMS sites were extrapolated to sub-Saharan Africa and South Asian regions to estimate region-wide MSD and LSD burdens. Attributable and excess mortality due to Cryptosporidium diarrhea were estimated. FINDINGS: Cryptosporidium was significantly associated with MSD and LSD below age 24 months. Among Cryptosporidium-positive MSD cases, C. hominis was detected in 77.8% (95% CI, 73.0%-81.9%) and C. parvum in 9.9% (95% CI, 7.1%-13.6%); 92% of C. parvum tested were anthroponotic genotypes. Annual Cryptosporidium-attributable MSD incidence was 3.48 (95% CI, 2.27-4.67) and 3.18 (95% CI, 1.85-4.52) per 100 child-years in African and Asian infants, respectively, and 1.41 (95% CI, 0.73-2.08) and 1.36 (95% CI, 0.66-2.05) per 100 child-years in toddlers. Corresponding Cryptosporidium-attributable LSD incidences per 100 child-years were 2.52 (95% CI, 0.33-5.01) and 4.88 (95% CI, 0.82-8.92) in infants and 4.04 (95% CI, 0.56-7.51) and 4.71 (95% CI, 0.24-9.18) in toddlers. We estimate 2.9 and 4.7 million Cryptosporidium-attributable cases annually in children aged <24 months in the sub-Saharan Africa and India/Pakistan/Bangladesh/Nepal/Afghanistan regions, respectively, and ~202,000 Cryptosporidium-attributable deaths (regions combined). ~59,000 excess deaths occurred among Cryptosporidium-attributable diarrhea cases over expected if cases had been Cryptosporidium-negative. CONCLUSIONS: The enormous African/Asian Cryptosporidium disease burden warrants investments to develop vaccines, diagnostics and therapies.

Burden and aetiology of diarrhoeal disease in infants and young children in developing countries (the Global Enteric Multicenter Study, GEMS): a prospective, case-control study.

BACKGROUND: Diarrhoeal diseases cause illness and death among children younger than 5 years in low-income countries. We designed the Global Enteric Multicenter Study (GEMS) to identify the aetiology and population-based burden of paediatric diarrhoeal disease in sub-Saharan Africa and south Asia. METHODS: The GEMS is a 3-year, prospective, age-stratified, matched case-control study of moderate-to-severe diarrhoea in children aged 0-59 months residing in censused populations at four sites in Africa and three in Asia. We recruited children with moderate-to-severe diarrhoea seeking care at health centres along with one to three randomly selected matched community control children without diarrhoea. From patients with moderate-to-severe diarrhoea and controls, we obtained clinical and epidemiological data, anthropometric measurements, and a faecal sample to identify enteropathogens at enrolment; one follow-up home visit was made about 60 days later to ascertain vital status, clinical outcome, and interval growth. FINDINGS: We enrolled 9439 children with moderate-to-severe diarrhoea and 13,129 control children without diarrhoea. By analysing adjusted population attributable fractions, most attributable cases of moderate-to-severe diarrhoea were due to four pathogens: rotavirus, Cryptosporidium, enterotoxigenic Escherichia coli producing heat-stable toxin (ST-ETEC; with or without co-expression of heat-labile enterotoxin), and Shigella. Other pathogens were important in selected sites (eg, Aeromonas, Vibrio cholerae O1, Campylobacter jejuni). Odds of dying during follow-up were 8·5-fold higher in patients with moderate-to-severe diarrhoea than in controls (odd ratio 8·5, 95% CI 5·8-12·5, p<0·0001); most deaths (167 [87·9%]) occurred during the first 2 years of life. Pathogens associated with increased risk of case death were ST-ETEC (hazard ratio [HR] 1·9; 0·99-3·5) and typical enteropathogenic E coli (HR 2·6; 1·6-4·1) in infants aged 0-11 months, and Cryptosporidium (HR 2·3; 1·3-4·3) in toddlers aged 12-23 months. INTERPRETATION: Interventions targeting five pathogens (rotavirus, Shigella, ST-ETEC, Cryptosporidium, typical enteropathogenic E coli) can substantially reduce the burden of moderate-to-severe diarrhoea. New methods and accelerated implementation of existing interventions (rotavirus vaccine and zinc) are needed to prevent disease and improve outcomes. FUNDING: The Bill & Melinda Gates Foundation.

Health care use patterns for diarrhea in children in low-income periurban communities of Karachi, Pakistan.

Diarrhea causes 16% of all child deaths in Pakistan. We assessed patterns of healthcare use among caretakers of a randomly selected sample of 959 children ages 0-59 months in low-income periurban settlements of Karachi through a cross-sectional survey. A diarrheal episode was reported to have occurred in the previous 2 weeks among 298 (31.1%) children. Overall, 280 (80.3%) children sought care. Oral rehydration solution and zinc were used by 40.8% and 2%, respectively; 11% were admitted or received intravenous rehydration, and 29% sought care at health centers identified as sentinel centers for recruiting cases of diarrhea for a planned multicenter diarrheal etiology case-control study. Odds ratios for independent predictors of care-seeking behavior were lethargy, 4.14 (95% confidence interval = 1.45-11.77); fever, 2.67 (1.27-5.59); and stool frequency more than six per day, 2.29 (1.03-5.09). Perception of high cost of care and use of home antibiotics were associated with reduced care seeking: odds ratio = 0.28 (0.1-0.78) and 0.29 (0.11-0.82), respectively. There is a need for standardized, affordable, and accessible treatment of diarrhea as well as community education regarding appropriate care in areas with high diarrheal burden.

Health care-seeking behavior for childhood diarrhea in Mirzapur, rural Bangladesh.

We evaluated patterns of health care use for diarrhea among children 0-59 months of age residing in Mirzapur, Bangladesh, using a baseline survey conducted during May-June 2007 to inform the design of a planned diarrheal etiology case/control study. Caretakers of 7.4% of 1,128 children reported a diarrheal illness in the preceding 14 days; among 95 children with diarrhea, 24.2% had blood in the stool, 12.2% received oral rehydration solution, 27.6% received homemade fluids, and none received zinc at home. Caretakers of 87.9% sought care outside the home; 49.9% from a pharmacy, and 22.1% from a hospital or health center. The primary reasons for not seeking care were maternal perception that the illness was not serious enough (74.0%) and the high cost of treatment (21.9%). To improve management of childhood diarrhea in Mirzapur, Bangladesh, it will be important to address knowledge gaps in caretakers' assessment of illness severity, appropriate home management, and when to seek care in the formal sector. In addition, consideration should be given to inclusion of the diverse care-giving settings in clinical training activities for diarrheal disease management.

Determinants of health care seeking for diarrheal illness in young children in urban slums of Kolkata, India.

Maternal practices regarding children's health care have been recognized as an important factor associated with mortality rates among children < 5 years of age. We focused on health care-seeking practices of primary caretakers of children < 5 years of age with diarrheal disease in Kolkata. We interviewed caretakers of 1,058 children in a baseline survey and 6,077 children on six subsequent surveys. The prevalence of diarrhea during the preceding 2 weeks was 7.9% in the baseline survey and 5.7% (lowest 3.5% to highest 7.8%) in subsequent surveys. Multivariate logistic regression showed that formal education of primary caretakers was associated with seeking care outside the home (odds ratio [OR] = 15.5; 95% confidence interval [CI] [2.5-85.7]; P = 0.002). Multinomial logistic regression showed that formal education of the primary caretaker (OR = 21.4; 95% CI [3.2-139.0]; P = 0.002) and presence of dry mouth during diarrhea (OR = 17.3; 95% CI [2.7-110.9]; P = 0.003) were associated with seeking care from licensed providers compared with the children for whom care was not sought outside of the home. This health care utilization and attitudes survey (HUAS) can serve as a tool to identify the factors that influence a better health care-seeking pattern in urban slums of Kolkata.

Health care seeking for childhood diarrhea in developing countries: evidence from seven sites in Africa and Asia.

We performed serial Health Care Utilization and Attitudes Surveys (HUASs) among caretakers of children ages 0-59 months randomly selected from demographically defined populations participating in the Global Enteric Multicenter Study (GEMS), a case-control study of moderate-to-severe diarrhea (MSD) in seven developing countries. The surveys aimed to estimate the proportion of children with MSD who would present to sentinel health centers (SHCs) where GEMS case recruitment would occur and provide a basis for adjusting disease incidence rates to include cases not seen at the SHCs. The proportion of children at each site reported to have had an incident episode of MSD during the 7 days preceding the survey ranged from 0.7% to 4.4% for infants (0-11 months of age), from 0.4% to 4.7% for toddlers (12-23 months of age), and from 0.3% to 2.4% for preschoolers (24-59 months of age). The proportion of MSD episodes at each site taken to an SHC within 7 days of diarrhea onset was 15-56%, 17-64%, and 7-33% in the three age strata, respectively. High cost of care and insufficient knowledge about danger signs were associated with lack of any care-seeking outside the home. Most children were not offered recommended fluids and continuing feeds at home. We have shown the utility of serial HUASs as a tool for optimizing operational and methodological issues related to the performance of a large case-control study and deriving population-based incidence rates of MSD. Moreover, the surveys suggest key targets for educational interventions that might improve the outcome of diarrheal diseases in low-resource settings.

Exploring household economic impacts of childhood diarrheal illnesses in 3 African settings.

Beyond the morbidity and mortality burden of childhood diarrhea in sub-Saharan African are significant economic costs to affected households. Using survey data from 3 of the 4 sites in sub-Saharan Africa (Gambia, Kenya, Mali) participating in the Global Enteric Multicenter Study (GEMS), we estimated the direct medical, direct nonmedical, and indirect (productivity losses) costs borne by households due to diarrhea in young children. Mean cost per episode was $2.63 in Gambia, $6.24 in Kenya, and $4.11 in Mali. Direct medical costs accounted for less than half of these costs. Mean costs understate the distribution of costs, with 10% of cases exceeding $6.50, $11.05, and $13.84 in Gambia, Kenya, and Mali. In all countries there was a trend toward lower costs among poorer households and in 2 of the countries for diarrheal illness affecting girls. For poor children and girls, this may reflect reduced household investment in care, which may result in increased risks of mortality.

Determinants of household costs associated with childhood diarrhea in 3 South Asian settings.

In addition to being a major cause of mortality in South Asia, childhood diarrhea creates economic burden for affected households. We used survey data from sites in Bangladesh, India, and Pakistan to estimate the costs borne by households due to childhood diarrhea, including direct medical costs, direct nonmedical costs, and productivity losses. Mean cost per episode was $1.82 in Bangladesh, $3.33 in India, and $6.47 in Pakistan. The majority of costs for households were associated with direct medical costs from treatment. Mean costs understate the distribution of costs, with 10% of cases exceeding $6.61, $8.07, and $10.11 in Bangladesh, India, and Pakistan, respectively. In all countries there was a trend toward lower costs among poorer households and in India and Pakistan there were lower costs for episodes among girls. For both poor children and girls this may reflect rationing of care, which may result in increased risks of mortality.

Changing GPs' antibiotic prescribing: a randomised controlled trial.

A randomised controlled trial involving 54 general practitioners (GPs) was conducted in Canberra, Australian Capital Territory from September 1997 to November 1999. In the first year of the study, 24 GPs, who constituted the active arm of the intervention group, were involved in the consideration of evidence and the development and implementation of a set of clinical guidelines for the treatment of acute respiratory infections. These guidelines were then endorsed in a meeting together with specialist colleagues. In the second year of the study the group of GPs who had been acting as controls, received a moderate intervention consisting of a brief educational event and distribution of the locally developed guidelines. We obtained data from January 1997 to December 1999 from the Health Insurance Commission on prescribing rates for 40 of the doctors in the study. The rate of prescribing was calculated as the number of antibiotic prescriptions per 100 Medicare services. The average yearly prescribing decreased significantly in the intensive intervention group and increased in the moderate intervention group, (p=0.026). A mixed effects longitudinal time series model was fitted to the data to account for seasonal variation of antibiotic prescribing and trends over time. The intensive intervention group significantly reduced their antibiotic prescribing over time compared to the moderate intervention group, (p<0.001). This study has shown that an intensive intervention in which general practitioners were actively engaged in development and consideration of the evidence base for the guidelines resulted in a significant fall in general antibiotic prescribing.