Antibiotic utilization pattern and its associated factors based on WHO AWaRe classification at a university hospital in the South of Thailand.

BACKGROUND: Antibiotic overuse accelerates antimicrobial resistance (AMR), posing a major global health threat. The World Health Organization (WHO) AWaRe classification promotes rational antibiotic use, recommending that at least 60% of antibiotic consumption belongs to the Access group. This study evaluated antibiotic prescribing patterns and factors associated with Watch/Reserve antibiotic use in a Thai tertiary hospital. METHODS: A cross-sectional study using longitudinal hospital databases (2021-2023) analyzed 28,892 antibiotic prescriptions from adult patients. Antibiotics were classified according to the 2023 WHO AWaRe framework. Antibiotic utilisation was quantified using Defined Daily Doses (DDDs), and generalised linear mixed-effects models were used to identify factors associated with Watch/Reserve versus Access antibiotic prescribing. RESULTS: Access antibiotics remained the predominant prescribing category, accounting for 69.2%, 58.9%, and 61.8% of prescriptions in 2021, 2022, and 2023, respectively, while Reserve antibiotics accounted for <0.5% annually. Watch antibiotic utilisation increased over time and exceeded Access antibiotics among hospitalised Civil Servant Medical Benefit Scheme (CSMBS) beneficiaries in 2023. Female sex, older age, and higher Charlson Comorbidity Index were independently associated with Watch/Reserve prescribing. Universal Health Coverage (UHC) beneficiaries had significantly higher odds of receiving Watch/Reserve antibiotics. CONCLUSIONS: Although Access antibiotics predominated, increasing Watch antibiotic use highlights opportunities to strengthen hospital-wide antimicrobial stewardship. Routine AWaRe-based monitoring may facilitate benchmarking and promote more rational antibiotic prescribing across healthcare settings.