Using Probability of Community-Acquired Pneumonia to Tailor Antimicrobials Among Inpatients

Low-risk patients with viral pneumonia do not benefit from and may be harmed by antibiotic therapy. In this study, an alert will appear in the electronic health record of patients undergoing molecular diagnostic testing for respiratory symptoms that provides options for diagnostic testing based on pre-test probability of bacterial infection. Patients with test results suggesting possible viral infection will be randomized to either usual care or to receive test results along with structured guidance from antimicrobial stewardship to consider discontinuing or de-escalating antibiotics. This guidance, which will include an explicit calculation of the post-test probability of bacterial infection based on considering risk factors, vital signs, symptoms, and available imaging, will be communicated to the primary care team via direct electronic message and a summary note in the patient's chart. The final decision on whether to continue antibiotic therapy will be up to the primary team. The primary outcome of interest will be in-hospital antibiotic use. Safety outcomes will include length of stay, readmissions, hospital-free days, and mortality.

Inclusion criteria

• Adult patients admitted to the University of Maryland Medical Center or University of Maryland Medical Center-Midtown Campus who are prescribed antibiotics for suspected community-acquired respiratory infection.
• Protocol-based diagnostic testing supports possible viral infection, either by positive molecular test or low procalcitonin value.

Exclusion criteria

• Hospitalization for >72 hours prior to protocol-based diagnostic testing.
• Previous molecular testing for viral infection during the same hospital encounter.
• Severely immunosuppressed, defined as having hematologic malignancy, solid organ tumor on chemotherapy, or solid organ transplant on immunosuppression