A proof-of-concept study to construct Bayesian network decision models for supporting the categorization of sudden unexpected infant death

Prevalence of sudden unexpected death of infants and its subcategories in low- or middle-income countries: a systematic review protocol

INTRODUCTION

Infant mortality in low or middle-income countries (LoMICs) is still triple that of high-income countries (HICs), and the high mortality burden regions are also weighed down by a triple or quadruple burden of disease such as HIV and tuberculosis; chronic illness; mental health; injury and violence; and maternal, neonatal and child mortality. Emerging data suggest that the sudden unexpected death in infancy (SUDI) burden in LoMICs is at least 10-fold that in HICs. While ending preventable deaths in the neonatal period has received some global attention, the postnatal period where SUDIs occur is a poorly understood and data-poor area in LoMICs. We propose conducting a systematic review to evaluate the burden and trends of SUDIs in LoMICs since 2004.

METHODS AND ANALYSIS

We will systematically search PubMed, Web of Science, Scopus, African Index Medicus, EBSCOHost, Google Scholar, WHOIS and WHO database to identify studies published from July 2004 until October 2024. Two reviewers will screen titles and abstracts and select full-text articles independently for review. We will use the tool developed by the South African Medical Research Council-Burden of Disease Review Manager (BODRevMan)-to assess the risk of bias for each included study. Risk of bias will be assessed for each included study. Information on the prevalence and/or incidence of SUDI and its subcategories and case definitions will be extracted from each article. Where possible, data on prevalence, incidence and subcategories will be pooled using a random effects meta-analysis to account for variability between estimates. The I2 statistic will establish the level of heterogeneity due to variation in estimates rather than chance. Results will be presented in tables and graphs. The systematic review will be reported according to the PRISMA 2020 checklist.

ETHICS AND DISSEMINATION

Ethical approval is not required as this is a protocol for a systematic review. Findings will be disseminated through peer-reviewed publications and conference presentations.

PROSPERO REGISTRATION NUMBER

CRD42023466162.

Autopsy for Medical Diagnostics: Finding the Cause of Sudden Unexpected Death through Investigation of the Cardiac Conduction System by Serial Sections

Sudden unexpected death (SUD) is a fatal event that occurs in an apparently healthy subject in a way that such an abrupt outcome could have not been predicted. SUD-including sudden intrauterine unexplained death (SIUD), sudden neonatal unexpected death (SNUD), sudden infant death syndrome (SIDS), sudden unexpected death of the young (SUDY), and sudden unexpected death in the adult (SUDA)-occurs as the first manifestation of an unknown underlying disease or within a few hours of the presentation of a disease. SUD is a major unsolved, shocking form of death that occurs frequently and can happen at any time without warning. For each case of SUD, a review of clinical history data and performance of a complete autopsy, particularly focused on the study of the cardiac conduction system, were carried out according to the necropsy protocol devised by the Lino Rossi Research Center, Università degli Studi di Milano, Italy. Research cases collected and selected for this study were represented by 75 SUD victims that were subdivided into 15 SIUD, 15 SNUD, 15 SUDY, and 15 SUDA victims. After a routine autopsy and clinical history analysis, death remained unexplained, and hence a diagnosis of SUD was assigned to 75 subjects, which included 45 females (60%) and 30 (40%) males ranging in age from 27 gestational weeks to 76 years. Serial sections of the cardiac conduction system disclosed frequent congenital alterations of the cardiac conduction system in fetuses and infants. An age-related significant difference in distribution among the five age-related groups was detected for the following anomalies of the conduction system: central fibrous body (CFB) islands of conduction tissue, fetal dispersion, resorptive degeneration, Mahaim fiber, CFB cartilaginous meta-hyperplasia, His bundle septation, sino-atrial node (SAN) artery fibromuscular thickening, atrio-ventricular junction hypoplasia, intramural right bundle branch, and SAN hypoplasia. The results are useful for understanding the cause of death for all SUD cases that were unexpected and would have otherwise remained unexplained, so as to motivate medical examiners and pathologists to perform more in-depth studies.

Development of a Risk Score to Predict Sudden Infant Death Syndrome

Sudden Infant Death Syndrome (SIDS) is the third leading cause of death among infants younger than one year of age. Effective SIDS prediction models have yet to be developed. Hence, we developed a risk score for SIDS, testing contemporary factors including infant exposure to passive smoke, circumcision, and sleep position along with known risk factors based on 291 SIDS and 242 healthy control infants. The data were retrieved from death certificates, parent interviews, and medical records collected between 1989−1992, prior to the Back to Sleep Campaign. Multivariable logistic regression models were performed to develop a risk score model. Our finalized risk score model included: (i) breastfeeding duration (OR = 13.85, p < 0.001); (ii) family history of SIDS (OR = 4.31, p < 0.001); (iii) low birth weight (OR = 2.74, p = 0.003); (iv) exposure to passive smoking (OR = 2.64, p < 0.001); (v) maternal anemia during pregnancy (OR = 2.07, p = 0.03); and (vi) maternal age <25 years (OR = 1.77, p = 0.01). The area under the curve for the overall model was 0.79, and the sensitivity and specificity were 79% and 63%, respectively. Once this risk score is further validated it could ultimately help physicians identify the high risk infants and counsel parents about modifiable risk factors that are most predictive of SIDS.