Antimicrobial Stewardship at a 100 Bed, Full-Service, Acute Care Hospital

Background:   Antimicrobial stewardship programs (ASPs) have resulted in decreased antimicrobial utilization, antibiotic resistance, Clostridium difficile infections, and drug acquisition costs. Although the majority of acute care hospitals in the United States are less than 200 beds, limited information about ASPs from these size facilities is available in the medical literature.

Objective:   To implement a formal ASP using a core strategy of prospective audit with intervention and feedback, and measure the impact on antimicrobial utilization.

Methods:   Las Colinas Medical Center is a full-service, 100 bed acute care hospital in Irving, Texas. In September 2009 an ASP team (infectious diseases (ID) physician and clinical pharmacist) began rounding for one hour, twice weekly in three adult care units (Medical Surgical, PCU, ICU) with a combined 44 beds. Charts for all patients receiving antimicrobial therapy for more than two days without an established ID consultation were reviewed. Recommendations were often made to discontinue, simplify, and shorten therapy using a standard communication form which also included options for broadening therapy and formal ID consultation when necessary. Compliance was voluntary and recommendations were scored for acceptance by the clinical pharmacist. There were no formulary restrictions or preauthorization requirements. Monthly antimicrobial utilization for all oral and parenteral agents in defined daily doses (DDD) (WHO Centre for Drug Statistics Methodology) per 1000 patient-days (PD) was calculated from dispensed drug quantities. Since these data were not available prior to January 2009, a baseline period of January 2009-August 2009 (pre-ASP) was designated for comparison to an intervention period of September 2009-August 2010 (ASP). Patient-days, admissions, and average length of stay (ALOS) were obtained from the hospital administrative database. An unpaired two-tailed t-test was used to compare pre-ASP and ASP mean, monthly utilization and ALOS with P<0.05 as the level of significance. 95% confidence intervals were calculated for the difference of means.

Results:   270 patient charts were reviewed and 228 of 291(78%) recommendations were accepted. Mean antimicrobial utilization for the three units combined decreased by 22% (P=0.007) from 1175 to 911 DDD per 1000 PD. Mean antibacterial utilization decreased by 22% (P=0.006) from 1094 to 853 DDD per 1000 PD. For the largest unit (Medical Surgical = 24 beds) mean antimicrobial utilization decreased by 29% (P=0.002) from 1018 to 725 DDD per 1000 PD and mean ALOS decreased by 8.4% (P=0.047) from 3.93 to 3.60 days.

Conclusions:   An ASP was successfully implemented at a 100 bed, full-service, acute care hospital with a significant decrease in antimicrobial and antibacterial utilization. There was an association with decreased length of stay on the Medical Surgical unit.