Predicting emergency department visits among children with asthma in two academic medical systems.

Objective: To develop and validate a predictive algorithm that identifies pediatric patients at risk of asthma-related emergencies, and to test whether algorithm performance can be improved in an external site via local retraining.Methods: In a retrospective cohort at the first site, data from 26 008 patients with asthma aged 2-18 years (2012-2017) were used to develop a lasso-regularized logistic regression model predicting emergency department visits for asthma within one year of a primary care encounter, known as the Asthma Emergency Risk (AER) score. Internal validation was conducted on 8634 patient encounters from 2018. External validation of the AER score was conducted using 1313 pediatric patient encounters from a second site during 2018. The AER score components were then reweighted using logistic regression using data from the second site to improve local model performance. Prediction intervals (PI) were constructed via 10 000 bootstrapped samples.Results: At the first site, the AER score had a cross-validated area under the receiver operating characteristic curve (AUROC) of 0.768 (95% PI: 0.745-0.790) during model training and an AUROC of 0.769 in the 2018 internal validation dataset (p = 0.959). When applied without modification to the second site, the AER score had an AUROC of 0.684 (95% PI: 0.624-0.742). After local refitting, the cross-validated AUROC improved to 0.737 (95% PI: 0.676-0.794; p = 0.037 as compared to initial AUROC).Conclusions: The AER score demonstrated strong internal validity, but external validity was dependent on reweighting model components to reflect local data characteristics at the external site.

Progression of Polysomnographic Abnormalities in Mucolipidosis II (I-Cell Disease).

ABSTRACT: Mucolipidosis II (Inclusion cell or I-cell disease) is an autosomal recessive lysosomal storage disorder clinically comparable to the mucopolysaccharidoses (MPS), characterized by progressive respiratory and neurologic deterioration. Sleep problems, especially obstructive sleep apnea (OSA) and disrupted sleep architecture, are observed in other lysosomal storage diseases but have not been described in mucolipidosis II. We report the progression of polysomnographic abnormalities in a child with mucolipidosis II, demonstrated by worsening sleep-related hypoventilation, OSA, and sleep state fragmentation despite advancing PAP therapy. Background slowing and reduction in spindle activity on limited EEG may reflect progressive CNS disease affecting thalamic neurons.

Relationship of sleep to pulmonary function in mucopolysaccharidosis II.

OBJECTIVE: To study the sleep characteristics, pulmonary function, and their relationships in an enzyme naive population of patients with mucopolysaccharidoses (MPS) II (Hunter syndrome). STUDY DESIGN: The analyzed subjects (30 patients with MPS II with a median age of 9 years) had been enrolled in an MPS II natural history study and a phase I/II enzyme replacement clinical study in which they underwent standard polysomnography including spirometry and plethysmography, if cooperative. Descriptive statistics and nonparametric correlation were performed for demographic, sleep, and pulmonary function variables. RESULTS: Median apnea-hypopnea index was 6.4, with obstructive sleep apnea observed in 27/30 subjects. Sleep architecture was characterized by diminished rapid-eye movement sleep duration (median 13%), and decline in sleep efficiency and slow-wave sleep duration in older individuals. Oxygen desaturation below 90% occurred in 26/30 subjects, and hypoventilation above 50 Torr occurred in 11/23 subjects with accurate end-tidal carbon dioxide recordings. Of 15 subjects with reliable spirometry, median forced expiratory volume in 1 second was below 80% predicted in 12/15 subjects. Forced expiratory volume in 1 second in percent-predicted was inversely related to apnea-hypopnea index and increase from baseline end-tidal carbon dioxide (P=.023, rs=-0.58), (P<.001, rs=-0.82). CONCLUSION: Sleep in MPS II is characterized by obstructive sleep apnea, altered sleep architecture, and impaired gas exchange. Sleep disruption is related to daytime pulmonary function, thus both systems should be evaluated when sleep abnormalities are suspected.