Abstract
IMPORTANCE: Urinary tract infection (UTI) is common in children, but the population incidence is largely unknown. Controversy surrounds the optimal diagnostic criteria and how to balance the risks of undertreatment and overtreatment. Changes in health care use during the COVID-19 pandemic created a natural experiment to examine health care use and UTI diagnosis and outcomes. OBJECTIVES: To examine the population incidence of UTI in children and assess the changes of the COVID-19 pandemic regarding UTI diagnoses and measures of UTI severity. DESIGN, SETTING, AND PARTICIPANTS: This retrospective observational cohort study used US commercial claims data from privately insured patients aged 0 to 17 years from January 1, 2016, to December 31, 2021. EXPOSURE: Time periods included prepandemic (January 1, 2016, to February 29, 2020), early pandemic (April 1 to June 30, 2020), and midpandemic (July 1, 2020, to December 31, 2021). MAIN OUTCOMES AND MEASURES: The primary outcome was the incidence of UTI, defined as having a UTI diagnosis code with an accompanying antibiotic prescription. Balancing measures included measures of UTI severity, including hospitalizations and intensive care unit admissions. Trends were evaluated using an interrupted time-series analysis. RESULTS: The cohort included 13 221 117 enrollees aged 0 to 17 years, with males representing 6 744 250 (51.0%) of the population. The mean incidence of UTI diagnoses was 1.300 (95% CI, 1.296-1.304) UTIs per 100 patient-years. The UTI incidence was 0.86 per 100 patient-years at age 0 to 1 year, 1.58 per 100 patient-years at 2 to 5 years, 1.24 per 100 patient-years at 6 to 11 years, and 1.37 per 100 patient-years at 12 to 17 years, and was higher in females vs males (2.48 [95% CI, 2.46-2.50] vs 0.180 [95% CI, 0.178-0.182] per 100 patient-years). Compared with prepandemic trends, UTIs decreased in the early pandemic: -33.1% (95% CI, -39.4% to -26.1%) for all children and -52.1% (95% CI, -62.1% to -39.5%) in a subgroup of infants aged 60 days or younger. However, all measures of UTI severity decreased or were not significantly different. The UTI incidence returned to near prepandemic rates (-4.3%; 95% CI, -32.0% to 34.6% for all children) after the first 3 months of the pandemic. CONCLUSIONS AND RELEVANCE: In this cohort study, UTI diagnosis decreased during the early pandemic period without an increase in measures of disease severity, suggesting that reduced overdiagnosis and/or reduced misdiagnosis may be an explanatory factor.