Development of a clinical prediction model and risk score for extended-spectrum beta-lactamase-producing urinary tract infection in a tertiary-care outpatient setting

Extended-spectrum beta-lactamase (ESBL)-producing organisms are common in outpatient urinary tract infections (UTIs). However, practical risk stratification tools for outpatient care are limited. In this retrospective cohort study, we included 993 culture-confirmed UTI episodes from 710 adults attending outpatient clinics at a tertiary-care hospital in Thailand between 2020 and 2024. Predictors of ESBL-producing UTI were identified using Firth’s penalized logistic regression and incorporated into a point-based clinical risk score. Model discrimination was assessed using the area under the receiver operating characteristic curve (AUROC). Internal validation was performed using bootstrap resampling. ESBL-producing UTI accounted for 34.4% of all UTIs. Bedridden status, underlying urinary tract disease, recent catheter exposure, prior ESBL-positive urine culture, recent systemic antibiotic exposure, current systemic corticosteroid therapy, and recent chemotherapy were independent predictors. The score demonstrated favorable apparent discrimination (AUROC 0.832, 95% patient-level bootstrap CI 0.801–0.862) and underwent patient-level bootstrap internal validation. At the cutoff score of ≥ 5, which provided the maximum Youden index in this study population, the sensitivity was 79.8%; specificity, 76.5%; positive predictive value, 64.1%; and negative predictive value, 87.8%. In summary, following external validation, the score may support empirical antibiotic selection and antimicrobial stewardship in similar tertiary-care outpatient populations.