Methods
The study was conducted using de-identified patient data from the
National Inpatient Sample (NIS) database, a part of the Healthcare Cost
and Utilization Project (HCUP), which is compiled by the agency for
Health care Research and Quality (AHRQ). The NIS database randomly
samples 20 percent of the discharges from participating hospitals in 47
US states and the District of Columbia. It contains data from more than
seven million hospital stays each year (8). Data from the years
2000–2017 were used for the purposes of this study. The study was exempt
from an institutional board review as the use of data from approved
unidentified public data sets is not considered human subject research.
The study population was identified using the International
Classification of Disease, Ninth and Tenth Revisions, Clinical
Modification (ICD-9&10-CM). Patients were included in the study if they
meet the following criteria. In essence, the patient was less than one
year of age, had a diagnosis of truncus arteriosus (ICD codes: 745.0 &
Q20.0), and had truncus arteriosus repair procedure (ICD-9-PCS:
35.83, 35.92 and corresponding ICD-10 procedure codes) during the index
of hospitalization. Patient data queried included demographics and
patient clinical characteristics. Patient demographic data collected
included: age, sex, race, primary payer, location of the hospital, type
of hospital, hospital bed size, the region of the hospital, type of
admission (elective or non-elective) and admission day of the week
(weekend or weekday). Primary outcomes were identified before the
analysis; these included death before hospital discharge, length of stay
(LOS), and hospital cost of charge. We compiled a list of common
procedures, comorbidities, and complications and evaluated their
prevalence in those who died during the hospitalization. For the
analysis of outcomes in patients with 22q11.2 deletion syndrome,
patients were stratified into two groups: those with and without 22q11.2
deletion syndrome using ICD code 279.11, 758.32, D82.1, and Q93.81. Data
were described using median (interquartile range) for continuous
variables as deemed appropriate. Categorical variables were described as
frequency (percentage). Survivors and Non-survivors were compared with
regards to demographic, clinical characteristics, and outcomes using
Mann-Whitney U test for continuous characteristics and Chi-square or
Fisher’s exact tests for categorical characteristics. Frequency of
truncus arteriosus repair, in-hospital mortality, and LOS were evaluated
over the years of the study. Trends were assessed for significance using
Jonckheere–Terpstra test. P < 0.05 was considered
significant. In an effort to minimize bias and to adjust for measurable
confounders, a univariate analysis was initially performed to identify
potential predictors of in-hospital mortality, thereafter, variables
with statistical significance (p < 0.15) were incorporated in
a multivariable analysis using a logistic regression model. We used the
SPSS software, version 25 (SPSS Inc., Chicago, IL) for all statistical
analyses.
Results:
Overall, there were 3009 infants with truncus arteriosus that met the
inclusion criteria. The majority of these patients (2026, 67.4%) had
their surgical repair at ≤ 28 days of age. There was no predominance of
either sex (male 51.2% vs. female 48.8%). The majority of the patients
were of the White race (51.6%), followed by the Hispanic race (23.3%).
Primary payer insurance was equally divided between Private insurance
and Medicaid (46.6% and 46.3%, respectively). The majority of the
patients were admitted to large bed-size hospitals (59.9%). Patients
discharged from the hospital were equally spread throughout the year
with no seasonal variation. The majority of the hospitalizations were
non-elective admissions (78.8%). In-hospital mortality was 326
(10.8%). Mortality was stable with a non-significant decrease over the
years of the study (Std. J-T statistics -1.063, p = 0.288, Figure 1).
Characteristics of survivors versus non-survivors are presented in table
1. Mortality rates were higher in neonates (12.9% vs. 6.4%, p
< 0.001). Patients with Black, Native American or Hispanic
race had significantly higher mortality than White race (16.5%, 15.6%,
13.5% vs. 7.9%, p < 0.001, respectively) and mortality in
patients with Medicaid insurance was significantly higher than those
with private insurance (14.4% vs. 8.0%, p < 0.001).
Mortality rates during elective admissions was 7.4% versus 10.6% for
non-elective admissions (p = 0.020).
Table 2 shows the outcomes of infants with repaired truncus arteriosus.
Non-survivors had prolonged median length of stay (non-survivors 29 days
[IQR 12–61] vs. survivors 24 days [IQR 14–40], p = 0.009),
this was associated with twofold increase in the cost of hospitalization
in the non-survivors (non-survivors $522,615 [$253,366–$842,009]
vs. survivors $285,114 [$170,681–$526,175], p <
0.001). Of note, 47.4% of the non-survivors were receiving
ExtraCorporeal Membrane Oxygenation (ECMO) life support during the
hospitalization versus 2.2% of survivors (OR = 39.4, p <
0.001). Prematurity (gestational age < 37 weeks) and low birth
weight (weight < 2500g) were associated with increased odds
risk of mortality (OR = 1.95, 95% CI: 1.40–2.72, p < 0.001,
and OR = 1.39, 95% CI: 0.95–2.03, p = 0.087, respectively).
Chromosomal anomalies other than 22q11.2 deletion syndrome were present
at a similar frequency in both survivors and non-survivors (survivors
4.7% vs. non-survivors 4.9%, p = 0.782). Surprisingly, 22q11.2
deletion syndrome was present less frequently in non-survivors
(non-survivors 20.9% versus survivors 28.0%, p = 0.007). Overall,
22q11.2 deletion syndrome was present in 27.2% of the patients. In
table 3, we compiled a list of in-hospital complications and evaluated
the association of these complications with in-hospital mortality (table
2). Stroke, acute kidney injury (AKI), pleural effusion, venous
thrombosis, intraventricular hemorrhage, and necrotizing enterocolitis
were all associated with increased odds risk of mortality (OR = 12.8,
4.37, 1.69, 4.85, 1.73 and 4.89, respectively). Pulmonary hypertension
was not associated with an increased odds risk of mortality.
A univariate analysis followed by a multivariable regression analysis
was performed to further analyze the dynamics between mortality
predictors (tables 3 and 4). The following factors were found to be
associated with increased mortality in the multivariate analysis:
prematurity (aOR = 2.43, 95% CI: 1.40–4.22, p = 0.002), diagnosis of
stroke (aOR = 26.2, 95% CI: 10.1–68.1, p < 0.001),
necrotizing enterocolitis (aOR = 3.10, 95% CI: 1.24–7.74, p = 0.015) and
presence of venous thrombosis (aOR = 13.5, 95% CI: 6.7–27.2, p
< 0.001). Private insurance and 22q11.2 deletion syndrome were
associated with lower odds of mortality (aOR = 0.34, 95% CI:
0.20–0.55, p < 0.001, and aOR = 0.54, 95% CI: 0.34–0.87, p
= 0.011, respectively). In the multivariate analyses: AKI and pleural
effusion were not associated with increased mortality. Patients who
received ECMO support or had cardiac catheterization procedure during
the hospitalization had increased odds of mortality (aOR = 82.0, 95%
CI: 44.5–151.4, p < 0.001, and aOR = 1.65, 95% CI:
0.98–2.77, p = 0.060, respectively). Successful cardiopulmonary
resuscitation during the hospitalization was not associated with a
significant increase in mortality (aOR = 1.29, 95% CI: 0.54–3.11, P =
0.570).