1048. A Randomized Controlled Trial of an Electronic Tool for Empiric Antibiotic Prescription: Results from the ANti-infective Stewardship using the WISCA tool in the Electronic Medical Record (AnSWER) Study

BACKGROUND: The Weighted-Incidence Syndromic Combination Antibiogram (WISCA) is a computer-based, clinical tool for improving initial antibiotic selection in the management of pneumonia, cellulitis, urinary tract infection (UTI) and intraabdominal infection (IAB). WISCA predicts the likelihood that an antibiotic regimen will be active against the expected organisms causing the infection for each of these syndromes. METHODS: We performed a crossover randomized controlled trial of the WISCA tool between July 1, 2015 and June 30, 2018 at 4 hospitals. WISCA suggests an empiric antibiotic regimen based on individual patients’ comorbidities, severity of illness, allergy profile, history of multidrug-resistant organisms (MDRO), and prior antibiotics. Within 24 hours of admission an ID physician-reviewed patient charts to determine whether one of the clinical syndromes was present. At intervention hospitals, patients’ providers were notified when a change in empiric therapy was suggested or antibiotics were recommended to be stopped (if no bacterial infection was present). Outcomes included readmission, mortality, C. difficile infection (CDI), MDRO infection, length of stay (LOS), and cost of antibiotics. RESULTS: 10,202 patients enrolled in the study with 4,451 (57% female, mean age 72) in the intervention arm and 5,751 (55% female, mean age 71) in the control arm. There were no significant differences in clinical outcomes for any of the syndromes. Among 2,146 patients determined to have no bacterial infection, WISCA intervention resulted in lower antibiotic cost during the hospital stay ($714.46 vs. $927.56, P < 0.01). When providers accepted the recommendation to stop antibiotics, there were fewer antibiotic days (mean 296 antibiotic days/1000 patient-days vs. mean 378 antibiotic days/1000 patient-days, P = 0.038) and no significant difference in mortality or readmission rates. No bacterial infection patients also experienced a nearly 3-fold lower rate of CDI vs. patients with infection (0.8% vs. 2.3%, P < 0.001). CONCLUSION: Although the use of the WISCA tool was not associated with a reduction in mortality, readmissions, or LOS, intervention to stop antibiotics for those with no bacterial infection was associated with reduced antibiotic use and cost savings. DISCLOSURES: All authors: No reported disclosures.