The French prospective multisite registry on sudden unexpected infant death (OMIN): rationale and study protocol

The French registry of sudden unexpected death in infancy (SUDI): a 7-year review of available data

The French "OMIN registry" was established in 2015 to collect nationwide standardised data concerning biological, clinical, environmental and social characteristics of sudden unexpected death in infancy (SUDI) and unexpected death in children aged 1-2 years. A biobank has existed since July 2020 to store biological samples for each case. This article aimed to detail (1) a brief history and the objectives of the registry; (2) a description of the methodology used; (3) the first results of the registry, i.e. the main characteristics of the cases included so far; (4) the process for accessing the data for research projects; and (5) issues regarding weakness and improvement and perspectives offered by the registry. On 31 May 2024, 1975 cases were included in the OMIN registry; on 31 December 2022, 4606 biological samples from 176 cases were collected. For each deceased child, different types of data are registered on an electronic case report form: socio-demographic data, personal and familial medical background, environment and feeding data, clinical data, and biological and imaging results. A strict and continuous quality control process is used to ensure the reliability of the data, in parallel with specific actions to improve the exhaustiveness of the registry. The OMIN registry database is one of the largest and the most complete databases on SUDI, especially in Europe, and the first in the world to associate a standardised biological sample collection with it. Perspectives of research provided by our registry are numerous and could be supported by national and international scientific collaborations.

CONCLUSION

 This article details the objectives and methods of the French registry of SUDI. It provides initial results relating to the population included in the register and the procedure for accessing the data.

WHAT IS KNOWN

• In Western Europe, France is one of the countries with the highest SUDI rate, making it the first cause of death of infants between 28 and 364 days. • The development of epidemiological tools on a national and international scale is essential to advance research into the determinants and risk factors of unexpected death in children under 2 years of age.

WHAT IS NEW

• The OMIN registry was created in France in 2015 to collect nationwide standardised social, environmental, clinical, and paraclinical data for cases of unexpected death in children aged 0 to 2 years. • To date, the OMIN registry has included 680 data from almost 2000 children unexpectedly deceased, completed by a biocollection since 2020. • Data from the OMIN registry, unique in its field, are freely available for scientific research teams, after acceptation by the scientific committee of the registry.

Impact of COVID-19 Pandemic Interventions on Sudden Unexpected Death in Infancy Incidence in France

OBJECTIVE

To study the impact of nonpharmaceutical interventions implemented during the COVID-19 pandemic on the monthly incidence of sudden unexpected death in infancy (SUDI) cases overall and those with a viral or bacterial identification.

STUDY DESIGN

We conducted an interrupted time-series analysis using seasonally adjusted Poisson regression models from the French national prospective and multicenter SUDI registry, that included all SUDI cases below the age of 1 year who died from 2016 to 2021 in mainland France.

RESULTS

Of 998 SUDI cases analyzed, 750 were recorded during the prepandemic period (January 2016 through March 2020) and 248 during the NPI period (April 2020 through December 2021). We found a significant seasonal pattern of overall monthly SUDI incidence, with a peak observed periodically from November to February. The monthly SUDI incidence decreased significantly from the prepandemic to NPI periods (adjusted incidence rate ratio 0.83 [95% CI 0.72-0.96]). In particular, the monthly incidence of SUDI cases with a viral or bacterial identification decreased significantly, while no significant difference was found for SUDI cases without a viral or bacterial identification.

CONCLUSIONS

Nonpharmaceutical interventions were associated with a significant change in the incidence of SUDI cases with a viral or bacterial identification. Further investigations are needed to analyze the pathophysiologic role of viruses and bacteria in the SUDI.

Risk factors for unexpected infant death among very premature infants in France

BACKGROUND

Prematurity is one of the risk factors for sudden unexpected infant death (SUID), a phenomenon that remains poorly explained.

MATERIALS AND METHODS

The analysis of specific factors associated with SUID among very premature infants (VPI) was performed through a retrospective review of data collected in the French SUID registry from May 2015 to December 2018. The factors associated with SUID among VPI were compared with those observed among full-term infants (FTI). Results are expressed as means (standard deviation [SD]) or medians (interquartile range [IQR)].

RESULTS

During the study period, 719 cases of SUID were included in the registry, 36 (incidence: 0.60 ‰) of which involved VPI (gestational age: 29.2 [2] weeks, 1157 [364]) g] and 313 (0.18 ‰) involved FTI (gestational age: 40 [0.8] weeks, 3298 [452] g). The infants' postnatal age at the time of death was similar in the two groups: 15.5 (12.2-21.8) vs. 14.5 (7.1-23.4) weeks. We observed low breastfeeding rates and a high proportion of fathers with no occupation or unemployment status among the VPI compared to the FTI group (31% vs. 55 %, p = 0.01 and 32% vs. 13 %, p = 0.05, respectively). Among the VPI, only 52 % were in supine position, and 29 % were lying prone at the time of the SUID (compared to 63 % and 17 %, respectively, in the FTI group).

CONCLUSION

This study confirms prematurity as a risk factor for SUID with no difference in the SUID-specific risk factors studied except for breastfeeding and socioeconomic status of the fathers. VPI and FTI died at similar chronological ages with a high proportion of infants dying in prone position. These results argue for reinforcement of prevention strategies in cases of prematurity.

Infant death from accidental suffocation and strangulation in bed in England and Wales: rare or unrecognised events?

BACKGROUND

Mandatory joint police and healthcare investigations of sudden unexpected death in infancy (SUDI) have been in place since 2008 in England. These include death scene examination with cause of death determined at multiprofessional case conference. Detailed evidence on sleep arrangements is available for most cases potentially leading to more being identified as due to accidental suffocation. SUDI remaining unexplained following investigation are classified as SIDS (sudden infant death syndrome) or unspecified deaths.Our objective was to determine whether detailed SUDI investigation has led to an increase in deaths classified as accidental suffocation or strangulation in bed (ASSB)?

METHODS

We obtained official mortality data for England and Wales for infants dying aged 0-364 days for International Statistical Classification of Diseases and Related Health Problems, 10th revision codes R95 (SIDS), R96, R98, R99 (unspecified causes of mortality) and W75 (ASSB) for the years 2000-2019.We calculated the mortality rate for ASSB, SIDS and unspecified causes based on total live births each year.

RESULTS

Unexplained SUDI decreased from 353 in 2000 to 175 in 2019, with the mortality rate falling from 0.58 to 0.29 per 1000 live births. The total postneonatal mortality rate fell during this time from 1.9 to 0.9 per 1000 live births suggesting this is a genuine fall. SIDS accounted for 70% of unexplained SUDI in 2000 falling to 49% in 2020 with a corresponding increase in R99 unspecified deaths.Few deaths were recorded as ASSB (W75), ranging between 4 in 2010 and 24 in 2001. The rate for ASSB ranged from 0.6 to 4.0 per 100000 live births.

CONCLUSIONS

There is a shift away from SIDS (R95) towards unspecified causes of death (R96, R98, R99). Improved investigation of deaths has not led to increased numbers of death identified as due to ASSB. There needs to be clear guidelines on accurate classification of deaths from ASSB to facilitate learning from deaths and inform prevention efforts.

Assessing retinal hemorrhages with non-invasive post-mortem fundus photographs in sudden unexpected death in infancy

INTRODUCTION

In the case of sudden unexpected death in infancy (SUDI), eye examination is systematic to detect retinal hemorrhages (RH) that are a crucial hallmark for abusive head trauma (AHT). The aim of this study is to assess the ability of non-invasive post-mortem fundus photographs (PMFP) to detect RH in case of SUDI.

METHODS

Bicentric retrospective analysis of consecutive cases of SUDI under 2 years of age were managed by two French SUDI referral centers with PMFP by RetCam (Clarity Medical Systems USA). PMFP were reviewed randomly, twice, by three independent ophthalmologists blinded for clinical data.

RESULTS

Thirty cases (60 eyes) were included. Median age was 3.5 months (interquartile [1.6; 6.0]). No child died of AHT. Image quality was sufficient to assert presence or absence of RH in 50 eyes (83%). Sufficient quality rate was significantly higher when the post-mortem interval was inferior to 18 h (91%, 42/46) as opposed to over 18 h (57%, 8/14, p=0.0096). RH were found in six eyes (10%), four children (13%), with excellent inter and intra-raters' concordance (Cohen's Kappa from 0.81 [0.56-1.00] to 1.00 [1.00-1.00]).

CONCLUSION

PMFP can detect RH in case of SUDI and is a relevant systematic screening test to be carried out as soon as the deceased child arrives in the hospital. It can decrease the need of eye removal for pathological examination, but further studies are needed to define the best decision algorithm.

Sudden Unexpected Death in Infancy: Current Practices in Virological Investigations and Documentation in the French Registry

OBJECTIVE

To describe pre-COVID-19 pandemic current practices in virological investigations, including type, frequency of samplings, and documented viruses, in sudden unexpected death in infancy (SUDI) and to compare results according to the cause of death.

STUDY DESIGN

Between May 2015 and December 2019, infants under 2 years of age included in the French SUDI registry were classified in one of 4 groups by causes of death according to the classification by Goldstein et al. : unexplained (SIDS), infectious, explained but noninfectious, and undetermined. Sampling sites and viruses detected were described, and then SIDS and explained deaths (control group) were compared.

RESULTS

Among 639 infants, 3.6% died of an established viral infection. From 23 sampling sites and 2238 samples, 19 virus species were detected. Overall, 43.3% of infants carried a virus, with no significant difference between SIDS infants and the control group (P = .06). We found wide variations in frequencies of samples by site (550 for nasopharynx to one for saliva). The highest positivity rate was from the nasopharynx (195/2238; 8.7%). Rhinovirus was the predominant virus detected (135/504; 26.8%), mostly in SIDS (83/254; 32.7%). We found no significant difference between positivity rates and distribution of viruses between the SIDS and control groups. At-autopsy virological analysis never contributed to determining the cause of death.

CONCLUSION

Current practices in virological investigations in SUDI are heterogeneous, with wide variability despite published guidelines. Investigations should be limited to the most relevant sites, and systematic at-autopsy sampling should be reconsidered. We found no association between virus detection and SIDS.

Non-immunization associated with increased risk of sudden unexpected death in infancy: A national case-control study

OBJECTIVE

In the context of vaccine scepticism, our study aimed to analyse the association between immunization status and the occurrence of sudden unexpected death in infancy (SUDI).

STUDY DESIGN

A multi-centre case-control study was conducted between May 2015 and June 2017 with data from the French national SUDI registry (OMIN) for 35 French regional SUDI centres. Cases were infants under age 1 year who died from SUDI and who were registered in OMIN. Controls, matched to cases by age and sex at a 2:1 ratio, were infants admitted to Nantes University Hospital. All immunization data for diphtheria (D), tetanus (T), acellular pertussis (aP), inactivated poliovirus (IPV), Haemophilus influenzae b (Hib), hepatitis B (HB) and 13-valent pneumococcal conjugate vaccine (PCV13) were collected by a physician. Cases and controls were considered immunized if at least one dose of vaccine was administered.

RESULTS

A total of 91 cases and 182 controls were included. The median age was 131 days (interquartile range 98-200.0) and the sex ratio (M/F) was about 1.1. For all vaccines combined (D-T-aP-IPV-Hib and PCV13), 22 % of SUDI cases versus 12 % of controls were non-immunized, which was significantly associated with SUDI after adjustment for potential adjustment factors (adjusted odds ratio 2.01 [95 % confidence interval 1.01-3.98, p = 0,047]).

CONCLUSIONS

Non-immunization for D-T-aP-IPV-Hib-HB and PCV13 was associated with increased risk of SUDI. This result can be used to inform the general public and health professionals about this risk of SUDI in case of vaccine hesitancy.

Protecting Infants from Sudden Unexpected Infant Death: Guidelines for Interventions during the Perinatal Period from the French National College of Midwives

With 300-400 annual deaths in France, sudden unexpected infant death (SUID) is the leading cause of mortality in France among infants from the end of their first through their 12th month of life. These clinical practice guidelines aim to identify strategies for (future) parents to prevent avoidable SUIDs. They are based on a narrative literature review and an analysis of the existing reports and guidelines available on the topic in 2019-2020. In summary, it is recommended that parents ensure that their infants sleep on their back on a firm, empty surface in a sufficiently ventilated environment, share the parental bedroom, and be breastfed and vaccinated. All of these actions create protective factors against SUID. Conversely, parents should know that several factors increase the risk of SUID: unsafe sleep, maternal smoking, passive smoking after birth, exposure to alcohol or other psychoactive substances, and excessive heat. Precis: Sudden Unexpected Infant Death prevention includes infants being breastfed and vaccinated, sleeping on their back, on a firm, empty surface, near parents, and that they are not overheated.

Abusive Head Trauma in Infants During the COVID-19 Pandemic in the Paris Metropolitan Area

Importance

The COVID-19 pandemic and the containment and mitigation measures taken were feared to be associated with increased child abuse.

Objective

To investigate the trend of abusive head trauma (AHT) incidence and severity in infants during the COVID-19 pandemic.

Design, Setting, and Participants

In a time-series analysis of a longitudinal, population-based, cohort study, all consecutive cases of AHT in infants younger than 12 months old referred between January 2017 and December 2021 to Necker Hospital for Sick Children, the single regional pediatric neurosurgery center for the Paris metropolitan area, were included. AHT was defined as 1 or more subdural hemorrhage and a positive multidisciplinary evaluation after a social, clinical, biological, and radiological workup. Data were analyzed from January to March 2022.

Main Outcomes and Measures

The primary outcome was the monthly incidence of AHT, which was analyzed using Poisson regression modeling. Secondary outcomes included mortality and severe morbidity and were studied with logistic and linear regressions. The monthly incidence of neurosurgical interventions for hydrocephalus was used as a control series.

Results

Among the 99 included infants with AHT (median [IQR] age, 4 [3-6] months; 64 boys [65%]), 86 of 99 (87%) had bridging vein thrombosis, 74 of 99 (75%) had retinal hemorrhages, 23 of 72 (32%) had fractures, 26 of 99 (26%) had status epilepticus, 20 of 99 (20%) had skin injuries, 53 of 99 (54%) underwent neurosurgical interventions, and 13 of 99 (13%) died. Compared with the prepandemic period (2017-2019), AHT incidence was stable in 2020 (adjusted incidence rate ratio, 1.02; 95% CI, 0.59-1.77) and then significantly increased in 2021 (adjusted incidence rate ratio, 1.92; 95% CI, 1.23-2.99). The severity of AHT worsened in 2021 in terms of mortality (odds ratio 9.39; 95% CI, 1.88-47.00). Other secondary outcomes and the control series were not significantly modified.

Conclusions and Relevance

In this cohort study, a marked increase in AHT incidence and severity occurred during the COVID-19 pandemic in the Paris metropolitan area. These results suggest the need for clinical awareness and preventive actions.

Prevalence, Characteristics, and Determinants of Suboptimal Care in the Initial Management of Community-Onset Severe Bacterial Infections in Children

Importance

Assessment of the quality of initial care is necessary to target priority actions that can reduce the still high morbidity and mortality due to community-onset severe bacterial infections (COSBIs) among children.

Objective

To study the prevalence, characteristics, and determinants of suboptimal care in the initial management of COSBIs.

Design, Setting, and Participants

This prospective, population-based, cohort study and confidential enquiry was conducted between August 2009 and January 2014 in western France, a region accounting for 15% of the French pediatric population (1 968 474 children aged 1 month to 16 years) and including 6 pediatric intensive care units (PICUs) and 35 emergency departments. Participants included all children aged 1 month to 16 years who died before PICU admission or were admitted to a PICU with a COSBI (ie, bacterial sepsis, including meningitis, purpura fulminans, and pulmonary, osteoarticular, intra-abdominal, cardiac, and soft-tissue severe infections). Data were analyzed from March to June 2020.

Exposures

Suboptimal care determined according to evaluation of 8 types of care: (1) the delay in seeking care by family, (2) the physician's evaluation of severity, (3) the patient's referral at the first consultation with signs of severity, (4) the timing and (5) dosage of antibiotic treatment, (6) the timing and (7) volume of fluid bolus administration, and (8) the clinical reassessment after fluid bolus.

Main Outcomes and Measures

Two experts assessed the quality of care before death or PICU admission as optimal, possibly suboptimal, or certainly suboptimal. The consequences and determinants of certainly suboptimal care were identified with multinomial logistic regression and generalized linear mixed models.

Results

Of the 259 children included (median [IQR] age, 24 [6-66] months; 143 boys [55.2%]), 27 (10.4%) died, and 25 (9.6%) had severe sequelae at PICU discharge. The quality of care was certainly suboptimal in 89 cases (34.4%). Suboptimal care was more frequent in children with sequelae (adjusted odds ratio [aOR], 5.61; 95% CI, 1.19-26.36) and less frequent in children who died (aOR, 0.16; 95% CI, 0.04-0.65) vs those surviving without sequelae. Factors independently associated with suboptimal care were age younger than 5 years (aOR, 3.15; 95% CI, 1.25-7.90), diagnosis of sepsis with no source (aOR, 5.77; 95% CI, 1.64-20.30) or meningitis (aOR, 3.39; 95% CI, 1.15-9.96) vs other severe infections, and care by a primary care physician (aOR, 3.22; 95% CI, 1.17-8.88) vs a pediatric hospital service.

Conclusions and Relevance

This study found that suboptimal care is frequent in the initial management of COSBI and is associated with severe sequelae. The paradoxical association with reduced risk of death may be explained by an insufficient adjustment on bacterial or host intrinsic factors. Management could be optimized by improving the quality of primary care, especially for young children.

Prevalence of positive toxicology analysis from the French national registry for sudden unexpected infant death (Tox-MIN)

BACKGROUND

Sudden unexpected infant death (SUID) remains the leading cause of postnatal mortality in many countries. French and international guidelines recommend a thorough examination with toxicology studies.

OBJECTIVES

The main objective was to determine the prevalence of toxic detection and positive analyses. The secondary objectives were to describe the different toxics and compare children with positive (Tox+) and negative results (Tox-) with other SUID risk factors.

DESIGN AND METHODS

We used the data registered from May 2015 to December 2018 by the French national SUID registry (OMIN). It collects data for all SUID cases admitted to any of the 35 participating French SUID referral centers.

RESULTS

Of the 624 SUID cases registered in the OMIN, a post-mortem toxicological analysis was performed in 398 infants. Thirty-six patients (9%) were positives for expected (Etox+ (n = 19 [53%], e.g., resuscitation drugs, regular treatments) and unexpected (UTox+) (n = 17 [47%]) toxics. The unexpected toxics were opioids (n = 8), cannabis (n = 4), cocaine (n = 3), cotinine (n = 2), carbon monoxide (n = 2), caffeine (n = 2), alcohol (n = 1) and GHB (n = 1). UTox + infants had a different seasonal distribution (p = .03), a higher incidence of inappropriate sleeping position and bedding at the time of death (respectively OR 3.8, p = .037 - OR 5.4, p = .026); inadequate body hygiene (OR 10.6, p = .0005), a younger maternal age (p = .045) and a higher rate of maternal drug abuse (OR 21.9, p = .0008).

CONCLUSION

The high rate of positive results warrants routine toxicology testing. The imputability of identified molecules is complicated by the presence of other known risk factors for SUID.

Epidemiology of Community-Onset Severe Bacterial Infections in Children and Its Evolution: A Population-Based Study in France

OBJECTIVES

To describe the epidemiology of community-onset severe bacterial infections in children and its recent evolution.

DESIGN

Prospective, observational, population-based study from 2009 to 2014.

SETTING

An administrative area accounting for 13% of the French pediatric population.

PATIENTS

All children 1 month to 16 years old who died before admission or were admitted to a PICU for a community-onset severe bacterial infection.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The incidence and mortality rate of community-onset severe bacterial infections were compared with data from a reference population-based study conducted between 2000 and 2006, that is, before national recommendations for antimeningococcal C and antipneumococcal generalized vaccinations. Among the 261 children included (median age 25 mo), 28 (10.7%) died. The main diagnoses were meningitis (n = 85; 32%) and purpura fulminans (n = 59; 22%). The most common isolated bacteria were Neisseria meningitidis (n = 75; 29%), including 47 (63%) cases of serogroup B and 15 (20%) serogroup C, Streptococcus pneumoniae (n = 49, 19%), and Staphylococcus aureus (n = 15; 6%). The incidence of community-onset severe bacterial infections was three per 100,000 person-years (95% CI, 2.6-3.3) and had decreased by 53% from the reference period. Mortality rate was 0.3 per 100,000 person-years (95% CI, 0.2-0.4) and had decreased by 73% from the reference period. The incidence of community-onset severe bacterial infections caused by N. meningitidis and S. pneumoniae was 0.8 and 0.5 per 100,000 person-years and had decreased by 70% and 67% from the reference period. The incidence of community-onset severe bacterial infections-related to Staphylococcus aureus was 0.16 per 100,000 person-years and had increased by 220% from the reference period.

CONCLUSIONS

The incidence and mortality rate of community-onset severe bacterial infections, except for S. aureus infection, have decreased in France. N. meningitidis and S. pneumoniae continue to account for many infections, which indicates the need for better vaccination coverage and spectrum.

Respiratory syncytial virus-associated mortality in a healthy 3-year-old child: a case report

Background

Respiratory syncytial virus (RSV) is the most frequently identified pathogen in children with acute lower respiratory tract infection. Fatal cases have mainly been reported during the first 6 months of life or in the presence of comorbidity.

Case presentation

A 47-month-old girl was admitted to the pediatric intensive care unit following sudden cardiopulmonary arrest occurring at home. The electrocardiogram showed cardiac asystole, which was refractory to prolonged resuscitation efforts. Postmortem analyses detected RSV by polymerase chain reaction in an abundant, exudative pericardial effusion. Histopathological examination was consistent with viral myoepicarditis, including an inflammatory process affecting cardiac nerves and ganglia. Molecular analysis of sudden unexplained death genes identified a heterozygous mutation in myosin light chain 2, which was also found in two other healthy members of the family. Additional expert interpretation of the cardiac histology confirmed the absence of arrhythmogenic right ventricular dysplasia or hypertrophic cardiomyopathy.

Conclusions

RSV-related sudden death in a normally developing child of this age is exceptional. This case highlights the risk of extrapulmonary manifestations associated with this infection, particularly arrhythmia induced by inflammatory phenomena affecting the cardiac autonomic nervous system. The role of the mutation in this context is uncertain, and it is therefore necessary to continue to assess how this pathogenic variant contributes to unexpected sudden death in childhood.

National registry for sudden unexpected deaths of infants and children in England: why do we need one and do families want one?

The sudden and unexpected death of an infant or child is devastating. An inability to explain why an infant or child died is difficult to accept for both families and professionals. No reliable national dataset exists to estimate precisely how many infants and children die unexpectedly each year in England. This lack of accurate epidemiological data belies the scale of this public health problem. Detailed controlled observational studies of infant deaths identifying risk factors and providing evidence-based advice for parents has seen a dramatic reduction in incidence over the last 30 years by almost 80% but greater knowledge is needed if future deaths of infants and older children are to be prevented and families optimally supported. We propose that a national registry of sudden unexpected deaths in infancy and childhood would accurately determine incidence, identify unknown risk factors and highlight good care practices, ensuring these can be standardised nationally. For such a project to be successful, however, parents must be at the heart of it. We held a consultation day between families, professionals and supporting charities (The Lullaby Trust, Child Bereavement UK, SUDC UK and CRY) to seek opinion on the desire for a registry and how best to ensure families are engaged. Here, we summarise our rationale for a registry and the feedback we received from attendees regarding their views of the proposal and the practical aspects of administering it.