Understanding three approaches to reporting sudden unexpected infant death in the USA.

INTRODUCTION: In the USA each year, there are approximately 3400 sudden unexpected infant (<1 year of age) deaths (SUID) which occur without an obvious cause before an investigation. SUID includes the causes of death (COD) undetermined/unknown, sleep-related suffocation/asphyxia and sudden infant death syndrome (SIDS); these are often called SUID subtypes. Three common ways SUID subtypes are grouped (SUID subtype groups) include International Classification of Diseases (ICD) Codes, SUID Case Registry Categories or Child Death Review (CDR)-Assigned Causes. These groups are often used to monitor SUID trends and characteristics at the local, state and national levels. We describe and compare the characteristics of these three SUID subtype groups. DISCUSSION: SUID subtype groups are distinct and not directly interchangeable. They vary in purpose, strengths, limitations, uses, history, data years available, population coverage, assigning entity, guidance documentation and information available to assign subtypes. CONCLUSION: Making informed decisions about which SUID subtype group to use is important for reporting statistics, increasing knowledge of SUID epidemiology and informing prevention strategies.

Characteristics of Sudden Unexpected Infant Deaths on Shared and Nonshared Sleep Surfaces.

OBJECTIVES: Describe characteristics of sudden unexpected infant deaths (SUID) occurring on shared or nonshared sleep surfaces. METHODS: We examined SUID among residents of 23 US jurisdictions who died during 2011 to 2020. We calculated frequencies and percentages of demographic, sleep environment, and other characteristics by sleep surface sharing status and reported differences of at least 5% between surface sharing and nonsharing infants. RESULTS: Of 7595 SUID cases, 59.5% were sleep surface sharing when they died. Compared with nonsharing infants, sharing infants were more often aged 0 to 3 months, non-Hispanic Black, publicly insured, found supine, found in an adult bed or chair/couch, had a higher number of unsafe sleep factors present, were exposed to maternal cigarette smoking prenatally, were supervised by a parent at the time of death, or had a supervisor who was impaired by drugs or alcohol at the time of death. At least 76% of all SUID had multiple unsafe sleep factors present. Among surface-sharing SUID, most were sharing with adults only (68.2%), in an adult bed (75.9%), and with 1 other person (51.6%). Surface sharing was more common among multiples than singletons. CONCLUSIONS: Among SUID, surface sharing and nonsharing infants varied by age at death, race and ethnicity, insurance type, presence of unsafe sleep factors, prenatal smoke exposure, and supervisor impairment. Most SUID, regardless of sleep location, had multiple unsafe sleep factors present, demonstrating the need for comprehensive safe sleep counseling for every family at every encounter.

Sudden Unexpected Infant Deaths: 2015-2020.

OBJECTIVE: Although the US infant mortality rate reached a record low in 2020, the sudden infant death syndrome (SIDS) rate increased from 2019. To understand if the increase was related to changing death certification practices or the coronavirus disease 2019 (COVID-19) pandemic, we examined sudden unexpected infant death (SUID) rates as a group, by cause, and by race and ethnicity. METHODS: We estimated SUID rates during 2015 to 2020 using US period-linked birth and death data. SUID included SIDS, unknown cause, and accidental suffocation and strangulation in bed. We examined changes in rates from 2019 to 2020 and assessed linear trends during prepandemic (2015-2019) using weighted least squares regression. We also assessed race and ethnicity trends and quantified COVID-19-related SUID. RESULTS: Although the SIDS rate increased significantly from 2019 to 2020 (P < .001), the overall SUID rate did not (P = .24). The increased SIDS rate followed a declining linear trend in SIDS during 2015 to 2019 (P < .001). Other SUID causes did not change significantly. Our race and ethnicity analysis showed SUID rates increased significantly for non-Hispanic Black infants from 2019 to 2020, widening the disparities between these two groups during 2017 to 2019. In 2020, <10 of the 3328 SUID had a COVID-19 code. CONCLUSIONS: Diagnositic shifting likely explained the increased SIDS rate in 2020. Why the SUID rate increased for non-Hispanic Black infants is unknown, but warrants continued monitoring. Interventions are needed to address persistent racial and ethnic disparities in SUID.

Explaining Sudden Unexpected Infant Deaths, 2011-2017.

BACKGROUND: Sudden unexpected infant death (SUID) represents a broad group of explained and unexplained infant deaths (<1 year old). Explaining why SUID occurs is critical to understanding etiology and prevention. Death certificate data cannot differentiate explained from unexplained SUID cases nor describe the surrounding circumstances. We report SUID rates by explained and unexplained categories and describe demographics and history of recent injury or illness using the Centers for Disease Control and Prevention SUID Case Registry. METHODS: The registry is a population-based surveillance system built on Child Death Review programs. Data are derived from multiple sources, including death certificates, scene investigations, and autopsy reports. Cases included SUIDs reported by states or jurisdictions participating in the registry during 2011-2017. Cases were classified into explained and unexplained categories by using the registry's classification system. Frequencies, percentages, and mortality rates per 100 000 live births were calculated. RESULTS: Of the 4929 SUID cases, 82% were categorized as unexplained. Among all cases, 73% had complete case information. Most SUIDs (72%) occurred in an unsafe sleep environment. The SUID mortality rate was 97.3 per 100 000 live births. Among explained and possible suffocation deaths, ∼75% resulted from airway obstruction attributed to soft bedding. CONCLUSIONS: Unsafe sleep factors were common in explained and unexplained SUID cases, but deaths could only be classified as explained suffocation for ∼20% of cases. Further analysis of unexplained deaths, including continued improvements to death scene investigation and documentation, may generate hypotheses for physiologic and genetic research, advance our understanding of gaps in SUID investigation, and enhance our understanding of infants at highest risk.

U-Shaped Pillows and Sleep-Related Infant Deaths, United States, 2004-2015.

OBJECTIVES: To describe infant deaths where a u-shaped pillow was under or around an infant and to describe cases classified as Explained Suffocation. METHODS: We examined demographics and circumstances of 141 infant deaths during 2004-2015 in the US National Fatality Review Case Reporting System with u-shaped pillows in the sleep environment. RESULTS: Most infants were < 6 months old (92%), male (58%), non-Hispanic White (53%), and of the nine explained suffocation deaths, four occurred when the u-shaped pillow obstructed the infant's airway; five occurred when the infant rolled off the pillow and their airway was obstructed by another object. CONCLUSIONS FOR PRACTICE: Although infrequent, infant deaths with u-shaped pillows have occurred. Health care providers may include discussion of the importance of caregivers following infant product packaging precautions and warning labels for commonly used consumer products, such as u-shaped pillows in their advice to caregivers.

Sleep-Related Infant Suffocation Deaths Attributable to Soft Bedding, Overlay, and Wedging.

BACKGROUND: Unintentional suffocation is the leading cause of injury death among infants <1 year old in the United States, with 82% being attributable to accidental suffocation and strangulation in bed. Understanding the circumstances surrounding these deaths may inform prevention strategies. METHODS: We analyzed data from the population-based Sudden Unexpected Infant Death Case Registry from 2011 to 2014. Cases categorized as explained suffocation with unsafe sleep factors (suffocation), per the Centers for Disease Control and Prevention's Sudden Unexpected Infant Death Case Registry classification system, were included and assigned a mechanism of obstruction, including soft bedding, overlay, or wedging. We calculated frequencies and percentages of suffocation deaths by mechanism and selected demographic and sleep-environment characteristics. RESULTS: Fourteen percent of sudden unexpected infant death cases were classified as suffocation; these cases were most frequently attributed to soft bedding (69%), followed by overlay (19%) and wedging (12%). Median age at death in months varied by mechanism: 3 for soft bedding, 2 for overlay, and 6 for wedging. Soft-bedding deaths occurred most often in an adult bed (49%), in a prone position (82%), and with a blanket (or blankets) obstructing the airway (34%). Overlay deaths occurred most often in an adult bed (71%), and infants were overlaid by the mother (47%). Wedging deaths occurred most often when the infant became entrapped between a mattress and a wall (48%). CONCLUSIONS: Safe sleep environments can reduce infant suffocation deaths. Increased knowledge about the characteristics of suffocation deaths can help inform prevention strategies by targeting highest-risk groups.

National and State Trends in Sudden Unexpected Infant Death: 1990-2015.

BACKGROUND: Sharp declines in sudden unexpected infant death (SUID) in the 1990s and a diagnostic shift from sudden infant death syndrome (SIDS) to unknown cause and accidental suffocation and strangulation in bed (ASSB) in 1999-2001 have been documented. We examined trends in SUID and SIDS, unknown cause, and ASSB from 1990 to 2015 and compared state-specific SUID rates to identify significant trends that may be used to inform SUID prevention efforts. METHODS: We used data from US mortality files to evaluate national and state-specific SUID rates (deaths per 100 000 live births) for 1990-2015. SUID included infants with an underlying cause of death, SIDS, unknown cause, or ASSB. To examine overall US rates for SUID and SUID subtypes, we calculated the percent change by fitting Poisson regression models. We report state differences in SUID and compared state-specific rates from 2000-2002 to 2013-2015 by calculating the percent change. RESULTS: SUID rates declined from 154.6 per 100 000 live births in 1990 to 92.4 in 2015, declining 44.6% from 1990 to 1998 and 7% from 1999 to 2015. From 1999 to 2015, SIDS rates decreased 35.8%, ASSB rates increased 183.8%, and there was no significant change in unknown cause rates. SUID trends among states varied widely from 41.5 to 184.3 in 2000-2002 and from 33.2 to 202.2 in 2013-2015. CONCLUSIONS: Reductions in SUID rates since 1999 have been minimal, and wide variations in state-specific rates remain. States with significant declines in SUID rates might have SUID risk-reduction programs that could serve as models for other states.

Racial and Ethnic Trends in Sudden Unexpected Infant Deaths: United States, 1995-2013.

BACKGROUND AND OBJECTIVES: Immediately after the 1994 Back-to-Sleep campaign, sudden unexpected infant death (SUID) rates decreased dramatically, but they have remained relatively stable (93.4 per 100 000 live births) since 2000. In this study, we examined trends in SUID rates and disparities by race/ethnicity since the Back-to-Sleep campaign. METHODS: We used 1995-2013 US period-linked birth-infant death data to evaluate SUID rates per 100 000 live births by non-Hispanic white (NHW), non-Hispanic black (NHB), Hispanic, American Indian/Alaska Native, and Asian/Pacific Islander racial/ethnic groupings. To examine racial/ethnic disparities, we calculated rate ratios with NHWs as the referent group. Unadjusted linear regression was used to evaluate trends (P < .05) in rates and rate ratios. The distribution and rates of SUID by demographic and birth characteristics were compared for 1995-1997 and 2011-2013, and χ2 tests were used to evaluate significance. RESULTS: From 1995 to 2013, SUID rates were consistently highest for American Indian/Alaska Natives, followed by NHBs. The rate for NHBs decreased significantly, whereas the rate for NHWs also declined, but not significantly. As a result, the disparity between NHWs and NHBs narrowed slightly. The SUID rates for Hispanics and Asian/Pacific Islanders were lower than the rates for NHWs and showed a significant decrease, resulting in an increase in their advantage over NHWs. CONCLUSIONS: Each racial/ethnic group showed a unique trend in SUID rates since the Back-to-Sleep campaign. When implementing risk-reduction strategies, it is important to consider these trends in targeting populations for prevention and developing culturally appropriate approaches for racial/ethnic communities.

The Sudden Death in the Young Case Registry: Collaborating to Understand and Reduce Mortality.

Knowledge gaps persist about the incidence of and risk factors for sudden death in the young (SDY). The SDY Case Registry is a collaborative effort between the National Institutes of Health, the Centers for Disease Control and Prevention, and the Michigan Public Health Institute. Its goals are to: (1) describe the incidence of SDY in the United States by using population-based surveillance; (2) compile data from SDY cases to create a resource of information and DNA samples for research; (3) encourage standardized approaches to investigation, autopsy, and categorization of SDY cases; (4) develop partnerships between local, state, and federal stakeholders toward a common goal of understanding and preventing SDY; and (5) support families who have lost loved ones to SDY by providing resources on bereavement and medical evaluation of surviving family members. Built on existing Child Death Review programs and as an expansion of the Sudden Unexpected Infant Death Case Registry, the SDY Case Registry achieves its goals by identifying SDY cases, providing guidance to medical examiners/coroners in conducting comprehensive autopsies, evaluating cases through child death review and an advanced review by clinical specialists, and classifying cases according to a standardized algorithm. The SDY Case Registry also includes a process to obtain informed consent from next-of-kin to save DNA for research, banking, and, in some cases, diagnostic genetic testing. The SDY Case Registry will provide valuable incidence data and will enhance understanding of the characteristics of SDY cases to inform the development of targeted prevention efforts.

Death Scene Investigation and Autopsy Practices in Sudden Unexpected Infant Deaths.

OBJECTIVE: To describe and compare sudden unexpected infant death (SUID) investigations among states participating in the SUID Case Registry from 2010 through 2012. STUDY DESIGN: We analyzed observational data from 770 SUID cases identified and entered into the National Child Death Review Case Reporting System. We examined data on autopsy and death scene investigation (DSI) components, including key information about the infant sleep environment. We calculated the percentage of components that were complete, incomplete, and missing/unknown. RESULTS: Most cases (98%) had a DSI. The DSI components most frequently reported as done were the narrative description of the circumstances (90%; range, 85%-99%), and witness interviews (88%, range, 85%-98%). Critical information about 10 infant sleep environment components was available for 85% of cases for all states combined. All 770 cases had an autopsy performed. The autopsy components most frequently reported as done were histology, microbiology, and other pathology (98%; range, 94%-100%) and toxicology (97%; range, 94%-100%). CONCLUSIONS: This study serves as a baseline to understand the scope of infant death investigations in selected states. Standardized and comprehensive DSI and autopsy practices across jurisdictions and states may increase knowledge about SUID etiology and also lead to an improved understanding of the cause-specific SUID risk and protective factors. Additionally, these results demonstrate practices in the field showing what is feasible in these select states. We encourage pediatricians, forensic pathologists, and other medicolegal experts to use these findings to inform system changes and improvements in DSI and autopsy practices and SUID prevention efforts.