Defining the Optimal Duration of Therapy for Hospitalized Patients With Complicated Urinary Tract Infections and Associated Bacteremia

Background. Limited data are available to guide effective antibiotic durations for hospitalized patients with complicated urinary tract infections (cUTIs). Methods. We conducted an observational study of patients ≥18 years at 24 US hospitals to identify the optimal treatment duration for patients with cUTI. To increase the likelihood patients experienced true infection, eligibility was limited to those with associated bacteremia. Propensity scores were generated for an inverse probability of treatment weighted analysis. The primary outcome was recurrent infection with the same species ≤30 days of completing therapy. Results. 1099 patients met eligibility criteria and received 7 (n = 265), 10 (n = 382), or 14 (n = 452) days of therapy. There was no difference in the odds of recurrent infection for patients receiving 10 days and those receiving 14 days of therapy (aOR: .99; 95% CI: .52–1.87). Increased odds of recurrence was observed in patients receiving 7 days versus 14 days of treatment (aOR: 2.54; 95% CI: 1.40–4.60). When limiting the 7-day versus 14-day analysis to the 627 patients who remained on intravenous beta-lactam therapy or were transitioned to highly bioavailable oral agents, differences in outcomes no longer persisted (aOR: .76; 95% CI: .38–1.52). Of 76 patients with recurrent infections, 2 (11%), 2 (10%), and 10 (36%) in the 7-, 10-, and 14-day groups, respectively, had drug-resistant infections (P = .10). Conclusions. Seven days of antibiotics appears effective for hospitalized patients with cUTI when antibiotics with comparable intravenous and oral bioavailability are administered; 10 days may be needed for all other patients.