Long-term outcome and risk factors for late mortality in Gram-negative bacteraemia: a retrospective cohort study.

Abstract Objectives The long-term outcomes of patients following Gram-negative bacteraemia (GNB) are poorly understood. We describe a cohort of patients with GNB over a two-year period and determine factors associated with late mortality (death between days 31 and 365 after detection of bacteraemia). Methods This is a single center retrospective observational cohort study of 789 patients with confirmed Escherichia coli, Klebsiella spp and Pseudomonas aeruginosa bacteraemias with a follow-up of one year. Multivariable survival analysis was used to determine the risk factors for late mortality in patients who survived the initial 30-day period of infection. Results Overall, one-year all-cause mortality was 36.2%, with 18.1% of patients dying within 30 days and 18.1% of patients suffering late mortality. An adverse antimicrobial resistance profile (HR 1.095 per any additional antimicrobial category, 95% CI 1.018 – 1.178, p = 0.014) and infection with Pseudomonas aeruginosa (HR 2.08, 95% CI 1.11 – 3.88, p = 0.022) were independent predictors of late mortality. Other significant factors included the Charlson Comorbidity Index and hospitalization length after the index blood culture. Conclusion Patients with GNB have a poor long-term prognosis. Risk factors for greater mortality at one year include comorbidity, hospitalization length, the infecting organism, and its resistance profile.