Trends in Respiratory Pathogen Testing at US Children's Hospitals

Importance Respiratory pathogen testing has been a common deimplementation focus. The COVID-19 pandemic brought new considerations for respiratory testing; recent trends in testing rates are not well understood. Objective To measure trends in respiratory testing among encounters for acute respiratory infections among children and adolescents (aged <18 years) from 2016 to 2023, assess the association of COVID-19 with these trends, and describe associated cost trends. Design, Setting, and Participants This retrospective serial cross-sectional study included emergency department (ED) encounters and hospitalizations in US children's hospitals among children and adolescents with a primary acute infectious respiratory illness diagnosis. Data were ascertained from the Pediatric Health Information System database from January 1, 2016, to December 31, 2023. Exposure Respiratory pathogen testing. Main Outcomes and Measures The primary outcome was the percentage of encounters with respiratory testing over time. Interrupted time series models were created to assess the association of COVID-19 with testing patterns. The inflation-adjusted standardized unit cost associated with respiratory testing was also examined. Results There were 5 090 923 eligible encounters among patients who were children or adolescents (mean [SD] age, 3.36 [4.06] years); 55.0% of the patients were male. Among these encounters, 87.5% were ED only, 77.9% involved children younger than 6 years, and 94.5% involved children without complex chronic conditions. Respiratory testing was performed in 37.2% of all encounters. The interrupted time series models demonstrated increasing prepandemic testing rates in both ED-only encounters (slope, 0.26 [95% CI, 0.21-0.30]; P < .001) and hospitalizations (slope, 0.12 [95% CI, 0.07-0.16]; P < .001). Increases in respiratory testing were seen at the onset of the COVID-19 pandemic in both ED-only encounters (level change, 33.78 [95% CI, 31.77-35.79]; P < .001) and hospitalizations (level change, 30.97 [95% CI, 29.21-32.73]; P < .001), associated initially with COVID-19-only testing. Postpandemic testing rates remained elevated relative to prepandemic levels. The percentage of encounters with respiratory testing increased from 13.6% [95% CI, 13.5%-13.7%] in 2016 to a peak of 62.2% [95% CI, 62.1%-62.3%] in 2022. While COVID-19-only testing decreased after 2020, other targeted testing and large-panel (>5 targets) testing increased. The inflation-adjusted standardized unit cost associated with respiratory testing increased from $34.2 [95% CI, $33.9-$34.6] per encounter in 2017 to $128.2 [95% CI, $127.7-$128.6] per encounter in 2022. Conclusions and Relevance The findings of this cross-sectional study suggest that respiratory testing rates have increased over time, with large increases at the onset of the COVID-19 pandemic that have persisted. Respiratory testing rates and related costs increased significantly, supporting a need for future deimplementation efforts.