Comparison of patient outcomes in a pharmacist-led outpatient parenteral antimicrobial therapy program

Purpose: Outpatient parenteral antimicrobial therapy (OPAT) is a therapeutic option meant to conserve healthcare resources when treating infections requiring the administration of IV antibiotics over a prolonged treatment course. In November 2016 at Franciscan Alliance Indianapolis, a dedicated pharmacist was hired to build a formal OPAT program for all patients discharged on IV antimicrobials under the care of the infectious disease physician group. The number of “good catch” events observed since the program’s formal inception has encouraged the creation of this study designed to examine the impact of this program on patient outcomes and antimicrobial stewardship. Methods: This was a retrospective chart review of adult patients with a discharge order for at least one IV antibiotic from Franciscan Health Indianapolis from December 1st, 2016 to May 31st, 2017. Patients receiving OPAT consults during their index hospital stay were compared to patients with similar infections who did not receive a consult. Patients residing in a nursing home or long-term care facility prior to admission were excluded from the analysis. Comparisons between patients with and without a readmission were also conducted in order to identify commonalities and differences in risk factors between groups. Demographic information collected included: the indication for parenteral antimicrobial therapy, sex, age, weight, and the type of provider prescribing the antimicrobials. The primary objective was 30-day readmission rate, with each instance being stratified based on the reason for readmission. Secondary objectives included: type of infection, antibiotic type, disposition at discharge, and duration of treatment. At least 122 patients were needed in each arm in order to detect a difference of 50 percent between treatment groups with a power of 80 percent for the primary objective. Results: No statistically significant difference between the readmission rates of the consult group and the non-consult group was observed (14.73% versus 31.82%, p\u3e0.05). The usage of antipseudomonal coverage (39.58% versus 86.36%, p\u3c0.0001) and ceftriaxone (9.47% versus 45.45%, p\u3c0.0001) was significantly lower in the consult group, demonstrating the potential improvements in antimicrobial stewardship an OPAT program can provide. Use of agents requiring therapeutic drug monitoring (TDM) was higher in the non-consult group, specifically vancomycin (86.36% versus 41.05%, p\u3c0.001) and gentamicin (6.32% versus 22.73%, p\u3c0.05). Furthermore, patients discharged to an extended care facility (ECF) or a short-term acute rehabilitation center (SAR) after receiving a consult were less likely to be readmitted (16.23% versus 54.55%, p\u3c0.001). The difference in use of drugs requiring TDM for patients sent to a SAR with a consult may also have contributed to this trend (50.46% versus 100%, p\u3c0.0001). Conclusion: The OPAT service did not show a statistically significantly reduction in the 30-day readmission rate during the first 6 months of the program. However, the number of patients without a consult meeting the inclusion criteria was markedly lower than anticipated, which led to the study being underpowered. Additionally, use of the program was associated with improved antimicrobial stewardship through reduced use of antipseudomonal coverage and ceftriaxone as well as reduced readmissions in patients requiring SAR placement