Antimicrobial stewardship program (ASP) is recommended to improve appropriate antimicrobial use, reduce bacterial resistance, unnecessary drug costs and enhance patient health outcomes. Two core strategies of ASP recommended as effective in guidelines are formulary restriction with drug preauthorization and prospective audit with feedback. Investigators will evaluate the effectiveness of the 2 strategies using antimicrobial utilization and patient outcomes.

Background: Antimicrobial stewardship program (ASP) is recommended to improve appropriate antimicrobial use, reduce bacterial resistance, unnecessary drug costs and enhance patient health outcomes. Two core strategies of ASP recommended as effective in guidelines are formulary restriction with drug preauthorization and prospective audit with feedback. Preauthorization is the current strategy used in our hospital, while most other hospitals in Taiwan and worldwide uses prospective audit with feedback. Preauthorization requires intensive manpower to maintain timeliness of antimicrobial use. This study will evaluate a policy change in strategy used for antimicrobial stewardship. Investigators will evaluate the effectiveness of the 2 strategies using antimicrobial utilization and patient outcomes.

Methods: During a stepwise change in the policy of the antimicrobial stewardship program in this hospital, the study will observe the differences between two standardized core strategies (preauthorization vs prospective audit) of ASP. Hospitalized patients aged 20 and above, requiring use of restricted antimicrobials will be recruited into the study. Signing of consent forms are waived since both strategies are already proven to be effective and are widely implemented in Taiwan and worldwide. Also, the evaluation of such policy changes will not impact on patient safety or patient rights. The conduction of the study will not require contacting patients and no clinical samples will be collected. All data required for analysis will be collected via a computerized patient care system. Patient data will be protected via de-linking. Patients will be excluded if admitted at or entered the intensive care unit within 48 hours of entry, and if infectious diseases consultation had been requested. Eligible patients will be randomized to either preauthorization, which is the current practice in the hospital; or prospective audit, that will be done at 48-72 hours after prescription, as is the current practice in other hospitals in Taiwan and worldwide. Managing physicians are not obligated to follow our advice and the investigators will not intervene in their management decisions. Primary outcomes include antimicrobial utilization, drug costs and patient outcomes such as length of stay and clinical improvement. The time spent on implementing these two strategies will be compared.

The study hypothesis is that the preauthorization group will impact on a reduction in antimicrobial cost and utilization, especially in the first 72 hours, when compared to prospective audit. However, patient outcomes will likely be similar. Antimicrobial stewardship programs using preauthorization as a core strategy compared to prospective audit with feedback have similar patient outcomes, but may reduce antimicrobial utilization.

Inclusion Criteria:

• In-hospital patients, aged 20 and above, with request from managing physicians for use of restricted antimicrobials.

Exclusion Criteria:

• Patients admitted to the intensive care unit at evaluation or within 48 hours of entry into the study.
• Patients with antimicrobial prescriptions prescribed during after-hours, including weekends and public holidays.
• Formal infectious disease consultations requested prior to randomization.
• Patients in the emergency department and outpatient department.