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.