Background: Despite the benefits of OPAT programs, readmission rates of up to twenty percent have been reported. In November 2016 at Franciscan Alliance Indianapolis, a dedicated pharmacist was assigned to build a formal OPAT program for all patients discharged on IV antimicrobials under the care of the infectious disease physician group. This study juxtaposed 30-day readmission rates and other patient outcomes for patients with and without an OPAT consult in order to assess how the program impacted patient care.
Methods: This was a retrospective cohort study comparing patients discharged on IV antimicrobials between December 1st, 2016 and May 31st, 2017. These patients were grouped based on whether they had a consult from the OPAT program. Thirty-day readmission rate, antimicrobial selection, discharge disposition, and treatment duration were collected and compared between groups. For the primary objective, at least 87 patients were needed to attain a power of 80% and detect a 30% difference between treatment groups.
Results: Out of 1,502 patients screened, 117 were deemed eligible and included (95 patients with a consult and 22 patients without). No statistically significant difference between the readmission rates of the consult group and the non-consult group was observed (14.74% vs. 31.80%, P =0.07). However, the consult group exhibited lower utilization of antipseudomonal coverage (38.95% vs. 86.40%, P<0.0001) and ceftriaxone (9.47% vs. 45.45%, P<0.001). Use of agents requiring closer therapeutic drug monitoring was higher in the non-consult group, specifically vancomycin (86.36% vs. 41.05%, P<0.001) and gentamicin (6.32% vs. 22.73%, P<0.05), despite the diminished intensity of follow-up for patients not followed by the service.
Conclusion: The OPAT service did not show a statistically significant reduction in 30-day readmission rate during the first 6 months of the program. However, this may have been due to insufficient power to detect the true difference between treatment arms. Additionally, use of the program was associated with improved antimicrobial stewardship through reduced use of antipseudomonal coverage and ceftriaxone.