Cohort profile: The WHO Child Mortality Risk Stratification Multi-Country Pooled Cohort (WHO-CMRS) to identify predictors of mortality through early childhood

Purpose To provide details of a pooled dataset that will be used to estimate absolute and relative mortality risks and other outcomes among children less than 59 months of age and the predictive performance of common risk exposures, both individually and in combination. Participants Children from birth to five years of age recruited at health facilities or community settings into 33 longitudinal observational or intervention studies in 18 low-and middle-income countries. Findings to date The dataset includes 75,287 children with a median age of 3 months (IQR 1, 12) at first measurement. In the pooled sample, 2,805 (3.7%) of the study children died. Data on birthweight was recorded in 18 studies, and gestational age in 13 studies. Among these, 14% of the included children were reported with low birthweight and 14% preterm birth. At first measurement, 33% of the children were stunted, 24% were wasted, and 35% underweight. 13% and 7% of caregivers reported that their child had acute diarrhoea or acute lower respiratory tract infection before the study visit, respectively. The proportion of children being breastfed at any study visit decreased from 99% at age <6 months to 77% in the age group 12-23 months. Child characteristics differed considerably between studies in the community and health care settings. The median study period was 15 months (IQR 7.6 to 18.4 months). Future plans The WHO Child Mortality Risk Stratification Multi-Country Pooled Cohort (WHO-CMRS) provides a large dataset including child, parental, and household characteristics from a diverse range of geographical, community and health system settings; planned analyses will examine knowledge gaps with the aim of informing global guidelines and their derivatives such as clinical management tools and implementation guidance, and to inform future research agendas. Strengths Limitations ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement WHO gratefully acknowledges funding support from USAID to establish the pooled database and conduct the main analyses. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The WHO Ethics Review Committee granted an exemption in March 2022 with protocol ID: ERC.0003745 I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Principle Investigators of the individual studies can be contacted for a request to access their data.