Changing Patterns of Use of Antibiotics in Adult Emergency Department Patients With a UTI: A National Perspective

Urinary tract infections (UTI) are common in the ED and treated with a variety of antibiotics. We evaluated the use of various antibiotic classes for treatment of UTI in adult ED patients before and after introduction of the boxed warning regarding the use of fluoroquinolones. We hypothesized that use of fluoroquinolones would drop significantly over time.

We performed a structured retrospective cross-sectional study using the TriNetX global health research network, including adult ED patients from 64 healthcare organizations. We included patients ages 18 and older who visited an ED between 2014 and 2024 who were diagnosed with a UTI (urethritis, cystitis, prostatitis, pyelonephritis) and treated with an antibiotic. The percentages of patients receiving a penicillin/beta lactam, fluoroquinolone, trimethoprim-sulfamethoxazole (TMX), nitrofuran, or fosfomycin were compared across years using repeated measures analysis of variance.

Between 2014 and 2024 there were 2,606,411 ED patients diagnosed with a UTI including 1,986,997 cystitis, 50,287 urethritis and urethral syndrome, 30,657 prostatitis, and 796,608 pyelonephritis. Their mean (SD) age was 56 (20), 69.4% were female, 64.8% were white, 21.5% were black and 10.9% were Hispanic/Latino. Use of penicillins/beta lactams increased from 53.9% in 2014 to 64.1% in 2017 to 86.1% in 2024. The use of fluoroquinolones decreased from 39.2% in 2014 to 28.3% in 2017 to 13.5% in 2024. The nitrofurans were used in 18.5% in 2014 remaining stable through 2019 then slightly falling to 11.8% in 2024. TMX was used in 12.8% in 2014 remaining above 10% through 2020 then falling to 7.9% in 2024. Fosfomycin was rarely used, ranging from 0.2% to 0.9% from 2014 to 2024. Similar patterns of antibiotic use were seen for cystitis and pyelonephritis. However, fluoroquinolone use remained high for patients with prostatitis ranging from 70.3% to 52.2% across the study period. The changes in the distribution of penicillins/beta lactams and fluoroquinolones between 2014 and 2024 were similar across age, sex, ethnicity and racial group.

Use of fluroquinolones to treat adult ED patients with a UTI has dramatically decreased while use of penicillins/beta lactams has dramatically increased from 2014 to 2024, especially after the FDA issued its fluroquinolone black box warning. There was no obvious age, sex, racial or ethnic bias in choice of antibiotics.