What Is the Risk for Mortality in an Infant After a Brief, Resolved, Unexplained Event (BRUE)?

William T. Basco, Jr., MD, MS


August 06, 2018

Brief, Resolved, Unexplained Events in Young Infants

In 2016, the American Academy of Pediatrics published a guideline on the evaluation of brief, resolved, unexplained events (BRUEs; formerly known as apparent life-threatening events [ALTEs]) that lack a diagnosis after appropriate evaluation.[1] That guideline offered a way to categorize infants who experience BRUEs into "lower risk" for future harm:

  • Not born prematurely

  • At least 2 months old

  • No previous BRUE episodes

  • An event lasting < 1 minute, and not requiring resuscitation by a medical professional

However, epidemiological data are insufficient to determine the degree of risk for future harm in infants with BRUEs. A recent study[2] sought to define the upper bound of the risk for death after a BRUE. Investigators pooled data from 10 studies published between 1970 and 2014 and two additional studies published from 2015 to 2017, with a total of 3005 infants. The follow-up period in these studies ranged from 1 week to 3 years. Any death that occurred > 4 months after the index BRUE was considered unlikely to be related to the BRUE.

Study Findings

There were a total of 12 deaths (0.4%) during the follow-up period, four of which occurred in infants older than 4 months, leaving a mortality rate of 8/3005 (0.26%) during the window of interest. Those eight deaths produced a mortality rate of 3.1 deaths/month/10,000 BRUEs, but the 95% confidence interval for this rate was wide (0.3 - 30.1). This mortality ratio corresponds to a risk for death after a BRUE of approximately 1/800. The baseline mortality rate among all infants during the same time period was approximately 1/500 within the first 4 months of life, or 1/1200 if neonatal deaths (before 28 days of age) were excluded.

A closer look at these 12 deaths revealed that four infants died during the initial hospitalization (three-fourths of those were the result of nonaccidental trauma events) and two died of seizure-related complications at 18 months and 5.5 years after the BRUE events. Three infants died of pneumonia, and another three were classified as sudden infant death syndrome.

In conclusion, the very low rate of death after a BRUE that falls within the ranges of all-infant mortality (1/500) and the "non-neonatal" death rate (1/1200) supports the 2016 recommendation to avoid admitting to the hospital infants who experienced a BRUE but are at lower risk for death after acute evaluation.


I've thought a lot about this question over the years, given that ALTEs and now BRUEs are such common reasons for admission to children's hospitals. Perhaps the frequency of such admissions will decline over time, but these data will be helpful when it comes to quantifying risk and counseling parents. Certainly, to anxious parents, no degree of risk is low enough to make them feel comfortable at discharge, but these data may help other parents and providers who are on the fence about admission to the hospital.


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