Adverse events leading to discontinuation of daptomycin versus vancomycin in outpatient parenteral antimicrobial therapy: a retrospective cohort study.

Objectives: To compare the adverse event rates between daptomycin and vancomycin in the outpatient parenteral antimicrobial therapy (OPAT) setting. Methods: This was a retrospective cohort study of patients treated with vancomycin or daptomycin in OPAT. Demographic and clinical data were abstracted from the electronic medical record. Vancomycin was dosed using Bayesian kinetics software to achieve a goal AUC of 400-600 mg h/L and daptomycin was a weight-based dose. The primary outcome was the occurrence of an adverse event resulting in a change in antimicrobial therapy or early discontinuation due to harm or injury. Secondary outcomes included measurement of time to adverse event occurrence and time in therapeutic range for the vancomycin group. The primary outcome was analyzed using a chi-square test. Results: A total of 175 patients were included, with 112 in the daptomycin group and 63 in the vancomycin group. The primary outcome of early discontinuation of OPAT therapy was not statistically different between the daptomycin and vancomycin groups [15/112 (13%) versus 9/63 (14%); P = 0.87]. The daptomycin group demonstrated a shorter median time to adverse event occurrence compared with the vancomycin group (12 versus 30 days). Conclusions: When comparing the rate of early discontinuation between daptomycin and vancomycin in OPAT, there was no significant difference between groups. These findings suggest that either agent may be considered in the OPAT setting depending on patient-specific factors. Dosing of vancomycin using Bayesian model dosing software may have led to a reduction of adverse events in the vancomycin group.