Intravenous to Oral Antibiotic Switch Therapy Among Patients Hospitalized With Community-Acquired Pneumonia

Community-acquired pneumonia (CAP) is a leading cause of hospital admissions and antimicrobial use. Clinical practice guidelines recommend switching from intravenous (IV) to oral antibiotics once patients are clinically stable.We conducted a retrospective cohort study of adults admitted with CAP and initially treated with IV antibiotics at 642 US hospitals from 2010 through 2015. Switching was defined as discontinuation of IV and initiation of oral antibiotics without interrupting therapy. Patients switched by hospital day 3 were considered early switchers. We compared length of stay (LOS), in-hospital 14-day mortality, late deterioration (intensive care unit [ICU] transfer), and hospital costs between early switchers and others, controlling for hospital characteristics, patient demographics, comorbidities, initial treatments, and predicted mortality.Of 378 041 CAP patients, 21 784 (6%) were switched early, most frequently to fluoroquinolones. Patients switched early had fewer days on IV antibiotics, shorter duration of inpatient antibiotic treatment, shorter LOS, and lower hospitalization costs, but no significant excesses in 14-day in-hospital mortality or late ICU admission. Patients at a higher mortality risk were less likely to be switched. However, even in hospitals with relatively high switch rates, <15% of very low-risk patients were switched early.Although early switching was not associated with worse outcomes and was associated with shorter LOS and fewer days on antibiotics, it occurred infrequently. Even in hospitals with high switch rates, <15% of very low-risk patients were switched early. Our findings suggest that many more patients could be switched early without compromising outcomes.