Abstract
BACKGROUND: Urinary tract infections (UTIs) affect 150 million people annually, with increased incidence among individuals over 60 years of age. Complicated UTIs (cUTIs), frequently caused by multidrug-resistant pathogens such as Escherichia coli and Klebsiella pneumoniae, present therapeutic challenges due to host factors and anatomical abnormalities. Carbapenem-resistant Enterobacterales (CRE) infections are of particular concern as they are associated with higher mortality and healthcare costs. This study aimed to compare the clinical and economic outcomes of cUTIs caused by CRE and carbapenem-susceptible Enterobacterales (CSE) at a referral hospital in Lima, Peru. MATERIALS AND METHODS: This retrospective cohort study included 200 patients with cUTI admitted to the emergency department. Patients were categorized into two groups: those with CRE-cUTI and those with CSE-cUTI. Data were collected from electronic medical records, including demographics, comorbidities, antimicrobial treatments, and clinical outcomes, with a primary focus on the 30-day mortality. Kaplan-Meier survival curves, log-rank tests, and generalized linear models were used to assess mortality risk factors. Adjusted relative risks (aRRs) were reported with 95% confidence intervals (CI). The final multivariate model was adjusted for three variables selected based on epidemiological relevance: carbapenem resistance, septic shock on admission, and Charlson comorbidity index. Hospitalization costs were calculated based on the hospital's fee schedule, whereas antibiotic costs were estimated by multiplying the unit cost of each antimicrobial by the total number of vials used for cUTI treatment. RESULTS: Twenty-one patients with CRE-cUTI and 179 with CSE-cUTI were enrolled. Third-generation cephalosporins and carbapenems were the most frequently used empirical antibiotics. Inappropriate empirical therapy was higher in the CRE group (76.2% vs. 51.4%, P=0.031). Among the CRE isolates, bla(NDM), bla(KPC), and bla(OXA-48) were identified. The targeted therapies included amikacin and colistin. The 30-day mortality rate was significantly higher in the CRE group than in the CSE group (38.1% vs. 11.7%, P=0.004). Multivariate analysis revealed that an increased Charlson comorbidity index (aRR 1.18; 95% CI, 1.08-1.30; P<0.001), septic shock on admission (aRR 3.57, 95% CI, 1.85-6.88; P<0.001), and CRE infection (aRR 2.19, 95% CI, 1.16-4.16; P=0.015) were significant predictors of mortality. Hospital stay costs were also higher in the CRE group ($4691.6 vs. $2920.9; P=0.032). CONCLUSION: Patients with cUTI caused by CRE experienced significantly higher 30-day mortality and hospital costs than those with cUTI caused by CSE. Effective prevention and management strategies are crucial to improve outcomes and reduce the economic burden of CRE-cUTIs.