Outcomes of Hospitalized Octogenarians with E. coli Bacteremia-Retrospective Cohort Study.

Background:Escherichia coli (E. coli) bacteremia is a significant cause of mortality, particularly in older adults. Limited data exists on clinical outcomes in octogenarians. This study aims to evaluate the clinical outcomes of E. coli bacteremia in octogenarians and determine whether appropriate empirical therapy leads to improved outcomes in this specific population. Methods: We conducted a retrospective cohort study of hospitalized patients with E. coli bacteremia at Beilinson Hospital from January 2012 to December 2022. Clinical characteristics, bacteremia sources, antibiotic resistance patterns, and patient outcomes were analyzed. The primary outcome was 30-day mortality. Multivariate regression was used to assess the impact of empirical antibiotic appropriateness on mortality. Results: The study included 2717 patients, of which 1042 (38%) were 80 years or older. Older patients had more comorbidities with increased rates of ischemic heart disease (20% vs. 14%, p < 0.01) and congestive heart failure (19% vs. 9%, p < 0.01). Patients with 3rd generation cephalosporin resistant strains were more likely to receive inappropriate empiric antibiotic therapy (54% vs. 23%, p < 0.01). Although appropriate empirical therapy was associated with improved survival in univariate analysis (19% vs. 28%, p < 0.01), it was not an independent predictor of 30-day mortality in multivariate analysis [adjusted OR = 1.10, 95% CI (0.64-1.81), p = 0.7]. A lower SOFA score [adjusted OR = 0.17, CI95% (0.01-0.31), p < 0.01] was associated with decreased 30-day mortality. Hypoalbuminemia was significantly associated with increased 30-day mortality [adjusted OR = 2.49, CI95% (0.1.56-3.97), p < 0.01]. Conclusions:E. coli bacteremia in octogenarians is associated with significant mortality. While timely appropriate antibiotic therapy is crucial, mortality appears to be more influenced by overall health status, comorbidities, and infection severity. Future research should focus on addressing these factors and developing personalized care strategies to improve survival in this high-risk group.