Western Journal of Emergency Medicine: Integrating Emergency Care with Population Health

Introduction: In urinary tract infections (UTI) sex-related differences in comorbidities, antimicrobial resistance, and outcomes have been described, but it remains unclear whether these disparities reflect sex-related biological mechanisms or are primarily explained by age and comorbidity, especially in emergency settings. Our objective was to evaluate sex-related differences in microbiology, antimicrobial resistance, and outcomes among adults with potentially multidrug-resistant UTIs presenting to the emergency department (ED), and to determine whether sex independently predicts multidrug-resistant infections and outcomes after adjustment for age and comorbidity.

Methods: We conducted a prospective multicenter study enrolling all adult patients with suspected or confirmed UTIs admitted to one of the eight EDs involved from February 2023–July 2024. Our primary outcome was the prevalence of multidrug-resistant UTIs and whether sex independently predicted multidrug-resistant infection after adjustment for age and comorbidity. Secondary outcomes included hospitalization, adequacy of empirical antibiotic therapy, clinical response at 7 days, and 7-day and 30-day all-cause mortality. Demographic, clinical, and microbiological data were compared by sex. To account for baseline differences in age and comorbidity burden (Charlson Comorbidity Index), multivariable logistic regression models were applied to identify independent predictors of multidrug-resistant infection, hospitalization, and 30-day mortality.

Results: We included 679 patients (358 males, 321 females). Mean age was 70.1 years (standard deviation 17.9) in males and 63.1 years (21.4) in females (P < .001). The Charlson Comorbidity Index was higher in males (2.50 [2.45]) than in females (1.85 [2.32]) (P = .01). Multidrug-resistant infection occurred in 107/321 females (33.5%) and 166/358 males (46.5%) (P = .02). Adequate empirical therapy was achieved in 213/321 females (66.2%) and 221/358 males (61.8%) (P = .10). Hospitalization occurred in 176/321 females (54.9%) and 175/358 males (48.8%) (P = .09). Seven-day mortality was 14/321 females (4.5%) and 28/358 males (7.9%) (P = .05), while 30-day mortality was 32/321 females (9.9%) and 50/358 males (14.0%) (P = .05). After adjustment for age and comorbidity, male sex remained independently associated with multidrug-resistant infection (adjusted odds ratio 1.45; 95% CI, 1.03–2.10, P sex = .02; P age = .01).

Conclusion: Male sex was independently associated with multidrug-resistant urinary tract infections in the emergency department, even after adjustment for age and comorbidity. These findings highlight the need for sex- and risk-based approaches to empirical therapy and antimicrobial stewardship in acute care settings.