Time to Appropriate Antibiotic Therapy Is an Independent Determinant of Postinfection ICU and Hospital Lengths of Stay in Patients With Sepsis

Abstract

Objective: To assess the timing of appropriate antibiotic therapy as a determinant of postinfection hospital and ICU lengths of stay in patients with sepsis.

Design: Single-center retrospective cohort study (January 2008-December 2012).

Setting: One thousand two hundred fifty-bed academic hospital.

Patients: One thousand fifty-eight consecutive blood culture positive patients.

Interventions: We retrospectively identified adult patients with severe sepsis or septic shock. Timing of appropriate antibiotic therapy was determined from blood culture collection time to the administration of the first dose of antibiotic therapy with documented in vitro susceptibility against the identified pathogen. We constructed generalized linear models to examine the determinants of attributable lengths of stay.

Measurements and main results: The median (interquartile range) time from blood culture collection to the administration of appropriate antibiotic therapy was 6.7 hours (0.0-23.3 hr). Linear regression analysis adjusting for severity of illness and comorbid conditions identified time to appropriate antibiotic therapy to be an independent determinant of postinfection ICU length of stay (0.095-d increase per hr of time to deliver appropriate antibiotic therapy; 95% CI, 0.057-0.132 d; p < 0.001) and postinfection hospital length of stay (0.134-d increase per hr of time to deliver appropriate antibiotic therapy; 95% CI, 0.074-0.194 d; p < 0.001). Other independent determinants associated with increasing ICU length of stay and hospital length of stay were mechanical ventilation (both ICU and hospital lengths of stay) and incremental peak WBC counts (hospital length of stay only). Incremental changes in severity of illness assessed by Acute Physiology and Chronic Health Evaluation II scores and comorbidity burden assessed by the Charlson comorbidity score were independently associated with decreases in ICU length of stay and hospital length of stay.

Conclusions: We identified time to appropriate antibiotic therapy in patients with sepsis to be an independent determinant of postinfection ICU and hospital lengths of stay. Clinicians should implement local strategies aimed at timely delivery of appropriate antibiotic therapy to improve outcomes and reduce length of stay.