Identification of severe acute pediatric asthma phenotypes using unsupervised machine learning

Abstract

AbstractRationaleMore targeted management of severe acute pediatric asthma could improve clinical outcomes.ObjectivesTo identify distinct clinical phenotypes of severe acute pediatric asthma using variables obtained in the first 12 h of hospitalization.MethodsWe conducted a retrospective cohort study in a quaternary care children's hospital from 2014 to 2022. Encounters for children ages 2–18 years admitted to the hospital for asthma were included. We used consensus k means clustering with patient demographics, vital signs, diagnostics, and laboratory data obtained in the first 12 h of hospitalization.Measurements and Main ResultsThe study population included 683 encounters divided into derivation (80%) and validation (20%) sets, and two distinct clusters were identified. Compared to Cluster 1 in the derivation set, Cluster 2 encounters (177 [32%]) were older (11 years [8; 14] vs. 5 years [3; 8]; p < .01) and more commonly males (63% vs. 53%; p = .03) of Black race (51% vs. 40%; p = .03) with non‐Hispanic ethnicity (96% vs. 84%; p < .01). Cluster 2 encounters had smaller improvements in vital signs at 12‐h including percent change in heart rate (−1.7 [−11.7; 12.7] vs. −7.8 [−18.5; 1.7]; p < .01), and respiratory rate (0.0 [−20.0; 22.2] vs. −11.4 [−27.3; 9.0]; p < .01). Encounters in Cluster 2 had lower percentages of neutrophils (70.0 [55.0; 83.0] vs. 85.0 [77.0; 90.0]; p < .01) and higher percentages of lymphocytes (17.0 [8.0; 32.0] vs. 9.0 [5.3; 14.0]; p < .01). Cluster 2 encounters had higher rates of invasive mechanical ventilation (23% vs. 5%; p < .01), longer hospital length of stay (4.5 [2.6; 8.8] vs. 2.9 [2.0; 4.3]; p < .01), and a higher mortality rate (7.3% vs. 0.0%; p < .01). The predicted cluster assignments in the validation set shared the same ratio (~2:1), and many of the same characteristics.ConclusionsWe identified two clinical phenotypes of severe acute pediatric asthma which exhibited distinct clinical features and outcomes.