Rates in Bronchiolitis Hospitalization, Intensive Care Unit Use, Mortality, and Costs From 2004 to 2018

IMPORTANCE: Over the last 2 decades, bronchiolitis guidelines and improvement efforts focused on supportive care and reducing unnecessary tests, treatments, and hospitalization. There have been limited population-based studies examining hospitalization outcomes over time. OBJECTIVE: To describe rates and trends in bronchiolitis hospitalization, intensive care unit (ICU) use, mortality, and costs. DESIGN, SETTING, AND PARTICIPANTS: This cohort study used population-based health administrative data from April 1, 2004, to March 31, 2018, to identify bronchiolitis encounters using hospital discharge diagnosis codes in Ontario, Canada. Children younger than 2 years with and without bronchiolitis hospitalization were included. Data were analyzed from January 2020 to July 2021. MAIN OUTCOMES AND MEASURES: Bronchiolitis hospitalization per 1000 person-years, ICU use per 1000 hospitalizations, mortality per 100 000 person-years, and costs per 1000 person-years adjusted to 2018 Canadian dollars and reported in 2018 US dollars. RESULTS: Among 2 336 446 included children, 1 199 173 (51. 3%) were male. During the study period, 43 993 children (1. 9%) younger than 2 years had 48 058 bronchiolitis hospitalizations at 141 hospitals. Bronchiolitis accounted for 48 058 of 360 920 all-cause hospitalizations (13. 3%) and 215 654 of 2 566 348 all-cause hospital days (8. 4%) in children younger than 2 years. Bronchiolitis hospitalization was stable over time, at 14. 0 (95% CI, 13. 6-14. 4) hospitalizations per 1000 person-years in 2004-2005 and 12. 7 (95% CI, 12. 2-13. 1) hospitalizations per 1000 person-years in 2017-2018 (annual percent change APC, 0%; 95% CI, -1. 6 to 1. 6; P =. 97). ICU admission increased significantly from 38. 1 (95% CI, 32. 2-44. 8) per 1000 hospitalizations in 2004-2005 to 87. 8 (95% CI, 78. 3-98. 0) per 1000 hospitalizations in 2017-2018 (APC, 7. 2%; 95% CI, 5. 4-8. 9; P <. 001). Over the study period, bronchiolitis mortality was 2. 8 (95% CI, 2. 3-3. 4) per 100 000 person-years and remained stable (APC, 1. 1%; 95% CI, -8. 4 to 11. 7; P =. 85). Hospitalization costs per 1000 person-years increased from 49 640 (95% CI, 49 617-49 663) in 2004-2005 to 58 632 (95% CI, 58 608-58 657) in 2017-2018 (APC, 3. 0%; 95% CI, 1. 3-4. 8; P =. 002). CONCLUSIONS AND RELEVANCE: From 2004 to 2018, bronchiolitis hospitalization and mortality rates remained stable; however, ICU use and costs increased substantially. This represents a major increase in high-intensity hospital care and costs for one of the most common and cumulatively expensive conditions in pediatric hospital care.