Readmissions for Recurrent Sepsis: New or Relapsed Infection?

OBJECTIVES: Sepsis hospitalizations are frequently followed by hospital readmissions, often for recurrent sepsis. However, it is unclear how often sepsis readmissions are for relapsed/recrudescent versus new infections. The aim of this study was to assess the extent to which 90-day readmissions for recurrent sepsis are due to infection of the same site and same pathogen as the initial episode. DESIGN: Retrospective cohort study. SETTING: University of Michigan Health System. PATIENTS: All hospitalizations (May 15, 2013 to May 14, 2015) with a principal International Classification of Diseases, Ninth revision, Clinical Modification diagnosis of septicemia (038.x), severe sepsis (995.92), or septic shock (785.52), as well as all subsequent hospitalizations and sepsis readmissions within 90 days. We determined organism and site of sepsis through manual chart abstraction. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: We identified 472 readmissions within 90 days of sepsis, of which 137 (29.1%) were for sepsis. In sepsis readmissions, the site and organisms were most commonly urinary (29.2%), gastrointestinal (20.4%), Gram negative (29.9%), Gram positive (16.8%), and culture negative (30.7%). Ninety-four readmissions (68.6%) were for infection at the same site as initial sepsis hospitalization. Nineteen percent of readmissions were confirmed to be same site and same organism. However, accounting for the uncertainty from culture-negative sepsis, as many as 53.2% of readmissions could plausibly due to infections with both the same organism and same site. CONCLUSIONS: Of the patients readmitted with sepsis within 90 days, two thirds had infection at the same site as their initial admission. Just 19% had infection confirmed to be from the same site and organism as the initial sepsis hospitalization. Half of readmissions were definitively for new infections, whereas an additional 34% were unclear since cultures were negative in one of the hospitalizations.