Methods
A prospective cohort study included all children <18 years old
who underwent tracheostomy placement between January 1, 2015 and
December 31, 2021 at Children’s Medical Center Dallas. This tertiary
care children’s hospital located in Dallas, Texas has a Level I
pediatric trauma center and a Level IV neonatal intensive care unit
(NICU). Patients who underwent tracheostomy at another facility or were
older than 18 years at the time of tracheostomy were excluded. This
study was approved by the UT Southwestern Medical Center Institutional
Review Board (STU 2019-1103).
The CHAMP prospective tracheostomy registry was developed as a quality
improvement initiative to track longitudinal outcomes of children after
tracheostomy. CHAMP maintains the registry with monthly data cleaning
performed to update each patient’s current status. Children with
tracheostomies are entered on the day of their tracheostomy and followed
until reaching 21 years old, tracheostomy decannulation, or death. The
registry is stored in the hospital electronic medical record system. All
visits to the healthcare system are subsequently captured (e.g.,
outpatient clinic, inpatient admission, emergency department visits,
etc.). For this study, data were collected and managed using REDCap
electronic data capture tools hosted at UT Southwestern Medical
Center.29 Data entry personnel were blinded to the
primary hypothesis of the study.
The cohort was divided into BPD and non-BPD patients. The diagnostic
definition of BPD continues to lack uniformity. However, children
classified as having BPD were generally premature infants who required
respiratory support for more than 28 days after birth. The primary
outcome measures were times to mechanical ventilator liberation,
tracheostomy decannulation, or death with tracheostomy still in place.
Censoring occured if the patient was lost-to-follow or aged out of the
system at 21 years old.
The following demographic variables were collected: age at tracheostomy
placement (months), sex (male or female), race (Native American or
Pacific Islander, Asian, African American or Black [hereto referred to
as Black]), ethnicity (Hispanic or non-Hispanic), primary payer
(Medicaid, private, other), and the caregiver’s preferred language
(English, Spanish, other). Both race and preferred language are
self-selected by the caregiver.
Comorbidities recorded, which were based on the International
Classification of Diseases, 9th Revision (ICD-9) andInternational Classification of Diseases, 10th Revision- Clinical
Modification (ICD-10-CM) codes included: BPD, preterm birth
(< 37 weeks gestatational age), congenital malformations,
newborn complications, maternal complications, bacterial sepsis of
newborn, birth hypoxia, respiratory distress syndrome, sepsis, cardiac
conditions, chronic respiratory failure, trauma, pulmonary hypertension,
and tracheobronchomalacia.
The Social Capital Atlas and Opportunity Atlas
(https://opportunityinsights.org/) datasets were used to measure the
cohort’s socioeconomic status (SES). The specific measures from the
Social Capital Atlas were economic connectedness (EC) and support ratio,
while the fraction of single parents and median household income were
obtained from the Opportunity Atlas. EC measures low-SES individuals’
connection to high-SES individuals within their ZIP code. It is
calculated by taking the average share of high-SES friends among low-SES
individuals in each ZIP code. The support ratio measures the density of
social networks within a ZIP code. It is calculated by taking the
proportion of within-ZIP code friendships where the pair share a third
mutual friend within the same ZIP code. The fraction of single parents
by county is defined as the percentage of households with children under
18 that a single parent heads. The median household income was also
determined at the county level. These measures can help glean insights
into the risk of economic hardship or challenges to caring for a child
with a tracheostomy.30-32
The child’s last known status was recorded as of their latest follow up
date. This included: alive with a tracheostomy, decannulated, died with
a tracheotomy in place, or lost to follow-up. Lost to follow-up was
defined as not being seen by any provider in the system in 24 months.
Further, the neurocognitive ability of the child (average, mild/moderate
impairment, and severe impairment) was documented. Severe impairment
refers to children with global developmental delay.
All statistics were performed with Stata Statistical Software
(StataCorp. 2023. Stata Statistical Software: Release 18 . College
Station, TX: StataCorp LLC.) The distribution of continuous data was
determined with quantile plots and the Shapiro-Wilk test for normality.
Due to the skewness of the data, continuous variables are presented as
median with interquartile ranges (IQR) (25th - 75th percentile).
Categorical data are presented as counts with percentages.
Kruskal-Wallis’s test for continuous variables was used and the Pearson
chi-square test for categorical variables to determine differences
between the two groups. A parametric regression survival analysis with
Weibull distribution was created to model the hazard ratios of the three
outcomes and adjust for confounding. In addition to BPD, the model
included variables with a P <.25 in the univariate
analysis. Variables where the P >.05 were
sequentially dropped until the final model was formed. Survival analysis
results are presented as hazard ratios (HR) with 95% confidence
intervals (CIs). The model was checked for fit using visual inspection
of goodness of fit plots.
A power analysis was performed using a two-sample log-rank test to
determine the required sample size for our study. Based on previous
research, an anticipated hazard ratio of 1.7 was considered, which
indicates a 70% higher risk of decannulation at any given time in the
BPD group compared to the non-BPD group. The significance level (alpha)
was set to 0.05, and the power at 0.8. This resulted in a total required
sample size of 184 participants, distributed evenly into two groups of
92 each. To correct for multiple comparisons, the Bonferroni method was
used, and the statistical significance was set toP <.0167 to account for our three primary outcomes. Of
note, secondary findings of significance are to be interpreted with
caution. Missing data were handled by listwise deletion.