Purpose
Older people have the highest use of antibiotics for acute and chronic urinary tract infection (UTI), despite diagnostic uncertainty and the growing problem of antibiotic resistance. We aim to describe use-patterns of UTI antibiotics two years prior to and following care home admission in Denmark.

Methods
This was a register-based nationwide drug-utilization study. In a cohort comprising all Danish residents admitted into a care home from 2015 to 2021, we described the use of UTI antibiotics, and examined differences between regions and individual care homes in rates of UTI antibiotic use. Further, we described trends in UTI-related contacts with hospitals in the two years prior to and following care home admission.

Results
The cohort comprised 101,297 residents (61% female; median age 84 years). UTI antibiotic use doubled from 7 to 14 treatments/100 residents/month two months prior to care home admission and remained at 10 treatments/100 residents/month the following two years. Prescription of pivmecillinam (55%) was most common. Primary care practitioners prescribed the majority (92%) of UTI antibiotics. UTI-related hospital contacts peaked at two months prior to care home admission, with 6 admissions/100 residents/month, subsequently dropping to 2 admission/100 residents/month. We found considerable variation in UTI antibiotic use, with 10% of care homes responsible for 20% of treatments in 2021.

Conclusion
Use of UTI antibiotics increased prior to and remained at a stable high level following care home admission in Denmark. Despite variation in use across regions and individual care homes, an overall decrease was seen throughout the years 2016–2021.