604 - Factors Associated with Adverse Drug Reactions Leading to Discontinuation of Vancomycin in Outpatient Parenteral Antimicrobial Therapy

Background: Over 250,000 patients receive outpatient parenteral antimicrobial therapy (OPAT) in the United States each year. Vancomycin is commonly used in OPAT but has a high rate of discontinuations due to adverse drug reactions (ADRs). Being able to predict the occurrence of these ADRs and assess their impact could improve the overall quality of OPAT services when utilizing vancomycin.

Methods: This was a retrospective chart review of all adult University of Utah Health (UUH) patients who received vancomycin OPAT and had planned follow-up with UUH infectious disease (ID) providers between October 25, 2018 and July 31, 2019. Patients were excluded if they were less than 18 years of age, pregnant, did not have planned follow up with UUH ID physicians, or were on any form of renal replacement therapy. The primary outcome assessed was discontinuation of vancomycin due to ADR, as documented by the ID provider. Type of ADR leading to discontinuation and 30-day unplanned readmission were also assessed.

Results: One hundred fifty-eight patients met inclusion criteria (n=158). The mean age of patients was 55 years with a median Charlson comorbidity score of 3. Most patients utilized a non-UUH infusion service (116, 73% vs 42, 27%) and utilized vancomycin as their sole antibiotic (83, 53%). The majority of patients were being treated for orthopedic infections (78, 49%). Twenty-eight patients discontinued  vancomycin OPAT due to an ADR (18%). The most common ADR leading to discontinuation was acute kidney injury (10, 36%). Variables associated with ADRs leading to discontinuation included utilization of UUH home infusion services (54% vs 21%, P < 0.001) and initial vancomycin plasma concentrations obtained less than 7 days after discharge (92% vs 71%, P < 0.001). The overall 30 day readmission rate was 10% and the rate among patients who experienced an ADR leading to discontinuation was higher than those who did not (25% vs 8%, P < 0.001).

Conclusion: The overall rate of discontinuation of vancomycin OPAT due to ADR in the UUH population is similar to what has been described in previous literature. The higher rate of unplanned readmission in the population of patients who experienced ADRs warrants further study. The results of this study will be utilized for future quality improvement interventions at our institution.