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.