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Hospitalizations for Pediatric Intoxication in Washington State, 1987-1997
France Gauvin, MD;
Benoît Bailey, MD, MSc;
Susan L. Bratton, MD, MPH
Arch Pediatr Adolesc Med. 2001;155:1105-1110.
ABSTRACT
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Background Intoxication (or poisoning) that necessitates hospitalization remains
an important source of morbidity in children.
Objective To determine changes, during an 11-year period (1987-1997), in the incidence
of hospitalization due to intoxication among children in Washington State
and circumstances of ingestion, agents used, hospital length of stay, charges,
and mortality.
Methods A computerized database of all hospital discharges (Comprehensive Hospital
Abstract Reporting System [CHARS] database) in Washington was used. Cases
included all children younger than 19 years with a primary or secondary diagnosis
for an intoxication or with an external cause of injury code (E code) for
an intoxication from 1987 to 1997.
Results There were 7322 hospitalizations (45 per 100 000 children per year);
the annual rate significantly decreased during the study period. Most patients
(75%) were teenagers. Sixty-five percent were female. Pharmaceutical agents
were used in 80% of cases. Analgesics were the most commonly used (34%), followed
by antidepressants (12%) and psychotropic drugs (8%). Nonpharmaceutical agents
were more prevalent in children younger than 12 years than in teenagers. Self-inflicted
intoxication was the most frequent cause identified by E codes (47%). Median
length of stay was 1 day, and median hospital charges were $2096. Mortality
was low (0.2%) and did not change significantly over time.
Conclusions Acute intoxication continues to be an important cause of hospitalization
in children. The type of agent involved did not change significantly over
time. Teenage girls continue as the highest risk group for suicide attempt
from ingestions. Self-inflicted intoxications were associated with higher
costs, length of stay, and readmissions. Although preventive measures anddevelopment
of poison centers have contributed to decrease mortality from acute intoxication
in children in the last 50 years, efforts need to be targeted toward suicide
prevention, especially among teenage girls.
INTRODUCTION
ACUTE INTOXICATION (or poisoning) in children can lead to serious complications,
hospitalization, and even death. Pediatric mortality from intoxications has
declined considerably in the last 30 years because of multiple preventive
measures. In 1950, there were 834 deaths from intoxications among US children
younger than 5 years; this number decreased to less than 50 per year in 1997.1 Nevertheless, acute intoxication remains an important
cause of illness in children. In 1997, 66 participating US poison centers
reported 2 192 088 human exposure cases.2
Children younger than 20 years were involved in two thirds of the cases.
The kind of agents used, the cause of intoxication, and the population
at risk may change over time; recognition of such changes might enhance preventive
measures and treatments to reduce morbidity and mortality related to childhood
intoxications. Few studies have evaluated childhood intoxication that results
in hospitalization. Our study describes the population of children hospitalized
for intoxication, from 1987 through 1997, in Washington State. We determined
the incidence of acute intoxications leading to hospitalization in children
and evaluated changes in intoxicating agents during the study period. We also
evaluated the circumstances of the intoxication to determine if changes occurred
during the study time. Finally, fatalities, hospital length of stay (LOS),
and hospital charges associated with acute intoxication were calculated.
METHODS
After institutional review board approval by the University of Washington
and the State of Washington Health and Human Services Department, we obtained
computerized information for persons hospitalized in Washington from 1987
through 1997. Data from 100 hospitals in Washington were included. All hospitalized
patients (younger than 19 years) with a discharge diagnosis of intoxication
were identified in the Comprehensive Hospital Abstract Reporting System (CHARS)
database. Subjects were included if they had a primary or secondary diagnosis
code for intoxication by drugs, medicinal, and biological substances (International Classification of Diseases, Ninth Revision
[ICD-9] codes 960-979); toxic effects of substances
chiefly nonmedical (codes 980-989); or nondependent abuse of drugs (code 305).3 However, cases with only nondependent use of tobacco
(code 305.1) were excluded because we did not consider it to be a primary
reason for hospitalization. The following external causes of injury codes
(ICD-9 E codes) were also identified to determine
the cause of the intoxication: unintentional poisoning by drugs, medicinal
substances, and biological substances (E850-E858); unintentional poisoning
by other solid and liquid substances, gases, and vapors (E860-E869); suicide
and self-inflicted poisoning by solid or liquid substances or by gases (E950-E952);
assault by poisoning (E962); and poisoning undetermined whether unintentionally
or purposely inflicted (E980-E982).3 Children
with E codes for intoxication were included as cases. All newborns and patients
transferred from other hospitals were excluded to avoid counting the same
patient twice. We also excluded all intoxication ICD-9
codes that were associated with an adverse reaction E code (E930-E949) to
avoid cases where the intoxication was iatrogenic or occurred during a hospitalization.
Demographic data (age, sex), hospital data (total charges, LOS, mortality),
and agents used were analyzed. Patients records were linked, and all subsequent
hospital admissions for intoxication during the study period were also evaluated.
The incidence of hospitalization for intoxication was determined using
census data in Washington (average of annual populations for a specified period).
Normally distributed continuous data were compared using the t test and 1-way analysis of variance. The Tukey B test was used to
adjust for multiple pairwise comparisons among the years of study. Nonparametric
data are reported as medians and 25th to 75th quartiles. Nonparametric data
were compared with the Kruskal-Wallis test and the Mann-Whitney test. Categorical
data were examined using the  2 test. SPSS 9.0 for Windows
(SPSS Inc, Chicago, Ill) was used for all statistical calculations. Statistical
significance was defined as P<.05.
RESULTS
There were 7322 hospitalizations for intoxication from 1987 to 1997
in Washington State. The average incidence of hospitalization for intoxication
in children was 45 per 100 000 children per year, and intoxication accounted
for 0.06% of all pediatric hospitalizations during the 11-year study period.
Children aged 12 to 18 years were the largest patient group (75%), followed
by children aged 0 to 5 years (20%) and children aged 6 to 11 years (5%).
Adolescents constituted most of the sample, and global results mainly reflect
this category of patients. Ingestions with more than 1 agent were reported
in 10% of cases. The median LOS was 1 day (range, 1-3 days); the median hospital
charges were $2096 (range, $1246-$3519). Only 15 children (0.2%) died.
Pharmaceutical agents were identified in 80% of the intoxications (Table 1). Analgesic agents were used in
a third of cases (34%), and acetaminophen was the most common medication in
this category (18%). Antidepressant agents constituted the next most common
category of medication leading to hospital admission (12%), followed by psychotropic
agents (8%) and anti-allergy or antiemetic drugs (6%). Nonpharmaceutical agents
were identified in 22% of patients with an intoxication. The most common agents
were alcohol (6%), followed by "street" drugs (4%) and fumes (3%).
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Table 1. Agents Involved in Hospitalized Pediatric Intoxications
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Features of the intoxication are presented by age categories in Table 2. Girls were significantly more
likely to have a hospital admission due to an intoxication in the teenager
group (2.5 times more frequent); boys were more frequently involved in all
younger groups. Comparing the 3 different age categories, analgesic ingestions
were significantly more common in teenagers (42%). Nonpharmaceutical agents
were more frequently involved in children younger than 12 years (36%) than
in teenagers (17%). Nonpharmaceutical agents included mainly bites or venom,
fumes, cleaning agents, and solvents or hydrocarbons. Multiple agents and
self-inflicted intoxications were significantly more common in teenagers compared
with younger children. Unintentional intoxications were least common among
teenagers (13%) compared with younger children (58% in the 6- to 11-year-old
group and 75% in the 0- to 5-year-old group). Number of readmissions, LOS,
and hospital charges were also significantly higher in teenagers.
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Table 2. Features of 7322 Intoxication Hospitalizations by Age Group
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Features of the intoxications and the relationship to years of study
are presented in Table 3. The
number of admissions significantly decreased during the study period (786
in 1987 to 592 in 1997). The mortality rate decreased from 0.3% to 0.1% during
the study period; however, this decline did not achieve statistical significance.
Median hospital LOS did not change; however, hospital charges significantly
increased. The causes of intoxication did not change between 1990 and 1993
compared with 1994 to 1997 (data before 1990 are not precise enough to conclude
the cause for this period). The most common agents involved in children hospitalized
for intoxication remained fairly constant during the 11-year period. However,
intoxication with analgesics, antidepressants, and psychotropic drugs was
significantly more frequent in the last period compared with the first 2 periods.
Acetaminophen ingestions became significantly more frequent over time (increased
from 15% to 22%; P<.001), whereas salicylic acid
use declined significantly (14% to 8%; P<.001).
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Table 3. Features of the 7322 Intoxication Hospitalizations by Time
Period
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Causes of the intoxications are presented in Table 4. E codes were not included in the statewide data set for
1987 and 1988. When these years were included, the cause of the intoxication
was undetermined in 25% of cases. Patients without an identified cause were
excluded from the table. Self-inflicted intoxication or suicide attempt was
the most frequent cause of intoxication (48%) and was more common in teenagers
(99%) and girls (77%). Self-inflicted intoxications were associated with significantly
longer hospital LOS and higher charges compared with unintentional intoxications
and assaults. Analgesics were the most frequent agents involved in all categories,
but were significantly more common in self-inflicted intoxications compared
with unintentional intoxications. Likewise, antidepressants were significantly
more common in self-inflicted intoxications compared with unintentional intoxications.
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Table 4. Causes of 7322 Intoxication Hospitalizations
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There were 15 fatalities. Deaths were more frequent in girls (73%) and
were more frequently caused by self-poisoning (47%). The agents involved in
the deaths were fumes (n = 4), barbiturates (n = 2), tricyclic antidepressants
(n = 2), unspecified agents (n = 2), and alcohol, plant, anticonvulsant, cardiac
medication, and acetaminophen (n = 1 each). The highest mortality rate was
for children aged 6 to 11 years (1.3%); the higher mortality in this group
was due to cases of fatal fume intoxications. Multiple ingestions were not
reported in any child who died. Hospital charges were significantly greater
in children who died ($9078) compared with children who did not ($2093); however,
LOS was similar in children who died (2 days) and those who survived (1 day).
A total of 244 patients had multiple admissions for intoxication during
the study period (520 admissions). Twenty-four had more than 2 admissions
(79 admissions). Six patients were hospitalized 4 to 5 times. Readmissions
were significantly more frequent among teenagers (93%) and girls (73%). In
patients with multiple admissions, self-inflicted intoxications were significantly
more common (66%) compared with unintentional poisoning (11%). Antidepressant
medications were the most common agents ingested by children with more than
2 hospital admissions. Hospital LOS and hospital charges also significantly
increased with subsequent readmission; however, mortality did not increase.
COMMENT
We found that the number of children in Washington State admitted to
a hospital for acute intoxication declined during the 11 years studied. The
medications and toxic agents involved in pediatric intoxications that required
hospitalization did not substantively change during the study period. Likewise,
the percentage of children with intoxication leading to hospital admission
due to self-inflicted intoxications did not change during the study period.
Our results differ from those of Rodriguez and Sattin,4
who found no significant difference between annual rates of hospitalizations
from poisonings between 1979 and 1983 in children (0-9 years old) in the United
States. We cannot fully explain these differences; however, they may be due
to regional differences in health care, our study population, or the longer
period of our study. Washington has a larger proportion of managed care (average
of 16% during the study period) than many other states, which may lead to
differences in access to primary and emergency care. Differences in referral
patterns and treatment advice provided by poison centers may exist. Differences
may in part be due to ethnic or socioeconomic differences in the populations.
Washington has a relatively homogeneous ethnic population, with 91% white
Americans in 1990. In the study by Rodriguez and Sattin,4
children of other ethnic backgrounds had a hospitalization rate for poisoning
that was 2.4 times that of white children.
In our study, the mortality rate was low (0.2%) and declined slightly
over time. This could be due to better recognition of intoxications or improved
prehospital or hospital care; however, we cannot determine which factors accounted
for the decline. It could also be because deaths occurring in the emergency
department or at home were not included. The fatal ingestions in our study
were similar to fatal intoxications reported in the Toxic Exposure Surveillance
Systems of the American Association of Poison Control Centers (TESS) database.2
In our study, analgesics constituted the most common cause of acute
intoxication leading to hospital admission in children. Our findings agree
with prior reports.2, 5, 6, 7, 8, 9
Ferguson et al10 reported that the most common
agents involved in intoxication leading to hospitalizations were analgesics
and that the number of salicylic acid intoxications was declining, whereas
the number of intoxications from acetaminophen had increased. We found the
same decline in salicylic acid intoxication, probably because salicylic acids
have largely been replaced by acetaminophen as the first-line antipyretic
and analgesic therapy, to prevent Reye syndrome. We also found that analgesic
ingestions were more common in older children compared with younger children.
This is probably because these medications are present in almost every home
and teenagers tend to act impulsively. Trinkoff and Baker11
pointed out that the availability of an agent was important in both unintentional
intoxications of preschool children and intentional intoxications among adolescents.
Similar to other reports,4, 5, 12
we found that children aged 12 to 18 years and 0 to 5 years were the most
likely to be admitted to the hospital with acute intoxication. As expected,
toddlers and school-aged children were usually involved in unintentional intoxication,
whereas teenagers generally had intentional intoxications. Most patients were
adolescents, thus influencing the agents used and the cause of intoxications
for the whole group.
Self-inflicted intoxication was the leading identified cause of intoxication-related
hospitalizations in Washington for children younger than 19 years. Poisoning
is a well-known method for suicide attempt in adolescent girls.9
From 1990 to 1997, the incidence of hospitalization for self-inflicted intoxications
did not significantly change. Hospitalization secondary to self-inflicted
intoxication did not increase in younger age groups either (<12 years old).
The number of self-inflicted intoxications from 1986 to 1989 was lower than
in the later periods. Many undetermined E codes were used in this period;
therefore, we cannot estimate the actual number of self-inflicted intoxications
or unintentional intoxications. Nevertheless, from 1986 to 1989, the ratio
of self-inflicted intoxication or unintentional intoxication is approximately
the same as in the other 2 periods (1.7:1 vs 1.5:1). No prior population-based
study was available to compare these results. A hospital-based study by McEvedy13 in London, England, showed a 108% increase of suicide
attempts by poisoning during a 4-year period and an increase in suicide attempts
in younger age groups over time. Unfortunately, our results cannot be compared
with those of this study because the populations are different. Furthermore,
the cause of the intoxications in our study was identified by E codes. Assignment
of the E codes relies on the medical record and was limited by missing data
that we could not verify.
Ingestion of multiple agents was more frequent in teenagers and when
the cause of intoxication was intentional. The use of multiple agents did
not increase during the study. These findings agree with the data from the
TESS report, where multiple ingestions account for 11% of cases.2
Multiple agent intoxications were more common in children who were admitted
more than twice with intoxications but were not associated with increased
mortality. Readmission was associated with use of potentially more toxic medications
but was not associated with higher mortality.
By using a hospital-based data set, we evaluated intoxication leading
to hospitalizations only. Thus, we report on a subset of intoxications, the
ones necessitating prolonged medical supervision and treatment. We cannot
determine how many intoxication-related deaths occurred outside the hospital
or in the emergency department. A recent study14
on poisoning-related visits to the emergency department in the United States
reported that for every 147 poison exposures, there are 59 emergency department
visits, 13 hospitalizations, and 1 death.
Our study has several limitations. First, the discharge codes recorded
in the discharge data were not verified. However, audits of the ICD-9 codes have reported that they are reliably reported in statewide
hospital discharge data.15 Second, we could
not confirm the E codes on which the cause of ingestion was reported. Finally,
we did not have information about children from Washington who received inpatient
care for acute intoxication in other states.
In conclusion, acute intoxications continue to be an important cause
of childhood hospitalization in Washington and other countries.16, 17, 18, 19
Pharmaceutical agents are more frequently involved in teenager intoxications,
whereas nonpharmaceutical agents are more prevalent in younger children. Importantly,
the type of agent involved did not change significantly during the study period,
and acetaminophen remains the most commonly ingested medication. Our data
also show that although intoxications are still a major health problem, the
hospitalization rate declined from 1987 to 1997 in Washington. This may be
secondary to preventive measures, such as the development of effective poison
centers and improvement in treatment and hospital care. The US Childhood Intoxication
Prevention Packaging Act of 1972 increased the safety of medications and home
products, and significant declines in emergency department visits for intoxication
(5.7 per 1000 in 1973 to 3.4 per 1000 in 1978) and in the mortality rate (from
2.1 per 100 000 to 0.5 per 100 000) were observed.20
In our study, the mortality rate is low but did not change significantly over
time. Prevention efforts should be continued to further decrease intoxication-related
hospitalizations and deaths. Prevention should include parental education
about transferring medications or household products from their original container
and use of child-resistant containers.21 Use
of a locked cabinet even when children are older and education of grandparents
is also important. Because female teenagers continue as the highest risk group
for a suicide attempt by ingestion of pharmacologic agents, prevention efforts
should be targeted to this population. The incidence of self-inflicted intoxications
did not decline in the last 8 years of our study. Self-inflicted intoxications
were associated with the highest costs (hospital charges), LOS, and number
of readmissions among children with poisonings that required hospitalization
in Washington. Suicide prevention in teenagers is essential but difficult
to realize. Implication of teachers, parents, and physicians should be emphasized.
AUTHOR INFORMATION
Accepted for publication March 29, 2001.
Presented at the Third World Congress on Pediatric Intensive Care, June
28, 2000, Montreal, Quebec.
What This Study Adds
Acute intoxication (or poisoning) in children can lead to serious complications,
hospitalization, and even death. Pediatric mortality from intoxications has
declined considerably in the last 30 years because of multiple preventive
measures. Nevertheless, acute intoxication remains an important cause of illness
in children. Our study describes the population of children hospitalized for
intoxication, from 1987 through 1997, in Washington State. The incidence of
hospitalizations for intoxication was 45 per 100 000 children per year;
the annual rate decreased during the 11-year period. Mortality was low (0.2%)
and did not change significantly over time. The type of agent involved did
not change significantly over time; acetaminophen remained the most common
ingestion. Teenage girls continue as the highest risk group for suicide attempt
from ingestions. Self-inflicted intoxications were associated with higher
costs, length of stay, and number of readmissions. Although preventive measures
and development of poison centers have contributed to decrease mortality from
acute intoxication in children, efforts need to be targeted toward suicide
prevention, especially among teenage girls.
From the Department of Anesthesiology, University of Washington School
of Medicine and Children's Hospital and Regional Medical Center, Seattle (Drs
Gauvin and Bratton); Divisions of Pediatric Intensive Care (Dr Gauvin), Clinical
Pharmacology and Toxicology (Dr Bailey), and Emergency Medicine (Dr Bailey),
Department of Pediatrics, Hôpital Ste-Justine, Université de
Montréal, Montreal, Quebec; and Department of Pediatrics, University
of Michigan and Mott Children's Hospital, Ann Arbor (Dr Bratton).
Corresponding author and reprints: France Gauvin, MD, Hôpital
Ste-Justine, Department of Pediatrics, 3175 Côte Ste-Catherine, Montreal,
Quebec, Canada H3T 1C5.
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