Latent Classes in Long-Term Functional Status in Children With Recurrent Critical Illness

Introduction: Critical illness may be associated with development of new morbidities, which manifest as worsening functional status during or after a pediatric intensive care unit (ICU) admission. Little is known about the characteristics that are associated with the longitudinal risk of morbidities after critical illness. We aimed to identify and describe trajectories of functional status in children with repeated ICU admissions and to describe clinical and demographic characteristics of each trajectory.


Methods: We included patients < 21 years old discharged from an index admission at one of 126 US ICUs participating in the Virtual Pediatric Systems database between 4/2017 and 12/2020 and followed through 12/2023. Functional status, a multidimensional marker of a child’s physiologic and cognitive status, was measured using the Functional Status Scale (FSS). FSS scores were collected by trained abstractors to reflect pre-illness baseline and status at ICU discharge for each encounter. Latent trajectory analysis was used to examine longitudinal patterns in patient FSS categories and identify trajectory classes. Optimal number of classes was selected by minimizing the Bayesian Information Criterion. We performed Kruskal-Wallis rank sum test and chi-square testing to assess differences between groups.


Results: 6038 children had >1 ICU encounter and comprised the analytic cohort. A linear trajectory model with 6 latent classes was identified: 3 stable over time (good [46.6%], moderate [18.7%], and severe dysfunction [15.5%]), 2 with worsening over time (good/mild dysfunction with significant decline [7.9%], good/mild dysfunction with moderate decline [5.7%]), and 1 with improvement over time (mild dysfunction with improvement [5.6%]). In univariable analysis, trajectory classes differed based on age, race and ethnicity, and diagnosis category, procedural exposure, severity of illness, and length of stay for the index admission.


Conclusions: In this multi-institutional database study using prospectively assigned functional status scores to describe a contemporary, heterogeneous patient population with recurrent ICU-based observations of functional status, we identified 6 classes of outcome trajectories with different clinical and demographic characteristics.