Trends in Hospital Costs and Levels of Services Provided for Children With Bronchiolitis Treated in Children's Hospitals.

Importance: Increasing hospital costs for bronchiolitis have been associated with increasing patient complexity and mechanical ventilation. However, the associations of illness severity and diagnostic coding practices with bronchiolitis hospitalization costs have not been examined.
Objective: To investigate the association of patient complexity, illness severity, and diagnostic coding practices with bronchiolitis hospitalization costs.
Design, Setting, and Participants: This retrospective cross-sectional study included 385 883 infants aged 24 months or younger who were hospitalized with bronchiolitis at 39 hospitals in the Pediatric Health Information System database from January 1, 2010, to December 31, 2019.
Exposure: Hospitalization for bronchiolitis.
Main Outcomes and Measures: Inflation-adjusted standardized unit cost (expressed in dollar units) per hospitalization over time. A nested subgroup analysis was performed to further examine factors associated with changes in cost.
Results: A total of 385 883 bronchiolitis hospitalizations were studied; the patients had a mean (SD) age of 7.5 (6.4) months and included 227 309 of 385 883 boys (58.9%) and 253 870 of 385 883 publicly insured patients (65.8%). Among patients hospitalized with bronchiolitis, the median standardized unit cost per hospitalization increased significantly during the study period (from $5636 [95% CI, $5558-$5714] in 2010 to $6973 [95% CI, $6915-$7030] in 2019; P < .001 for trend). Similar increases in cost were observed among subgroups of patients without a complex chronic condition and without the need for mechanical ventilation. However, costs for patients without a complex chronic condition or mechanical ventilation, who received care outside the intensive care unit did not change in an economically significant manner (from $4803 [95% CI, $4752-$4853] in 2010 to $4853 [95% CI, $4811-$4895] in 2019; P < .001 for trend), suggesting that intensive care unit use was a primary factor associated with cost increases. Substantial changes in coding practices were observed. Among patients hospitalized with bronchiolitis, 1.2% (95% CI, 1.1%-1.3%) were assigned an APR-DRG (All Patient Refined Diagnosis Related Group) for respiratory failure in 2010, which increased to 21.6% (95% CI, 21.2%-21.9%) in 2019 (P < .001 for trend). Increased costs and coding intensity were not accompanied by objective evidence of worsening illness severity.
Conclusions and Relevance: This cross-sectional study suggests that hospitalized children with bronchiolitis are receiving costlier and more intensive care without objective evidence of increasing severity of illness. Changes in coding practices may complicate efforts to study trends in the use of health care resources using administrative data.