Nephrotoxicity Risk and Clinical Effectiveness of Continuous versus Intermittent Infusion Vancomycin Among Patients in an Outpatient Parenteral Antimicrobial Therapy Program.

STUDY
OBJECTIVE: To compare rates of nephrotoxicity, time to nephrotoxicity onset, and clinical failure among patients who received continuous infusion (C-I) or intermittent infusion (I-I) vancomycin in an outpatient parenteral antimicrobial therapy (OPAT) program. Nephrotoxicity was defined as an increase in serum creatinine greater than 0.5 mg/dl or a 50% increase from baseline for two consecutive measurements while receiving vancomycin during OPAT. Clinical failure was defined as unplanned readmission, extension of therapy, or change in antibiotics.
DESIGN: Single-center propensity score-matched retrospective cohort study.
SETTING: OPAT clinic affiliated with two nearby hospitals. PATIENTS: We identified 300 patients who received C-I or I-I vancomycin for at least 1 week in the OPAT program between October 1, 2017, and March 31, 2019. Propensity score matching based on age, sex, and infection was performed to minimize differences in patient characteristics between groups.
MEASUREMENTS AND MAIN RESULTS: After propensity score matching and exclusion criteria, 74 patients were included in each cohort. Continuous infusion vancomycin was associated with a 3.22-fold decrease in nephrotoxicity risk (C-I 6.8% [5/74 patients] vs I-I 18.9% [14/74 patients]; odds ratio 3.22, 95% confidence interval 1.10-9.46, p=0.027) and a significantly slower onset to nephrotoxicity compared with I-I (p=0.035). No statistically significant difference in clinical failure rates was observed between the C-I and I-I groups (13.5% [10/74 patients] vs 23.0% [17/74 patients], p=0.147).
CONCLUSION: In an OPAT setting, C-I vancomycin was associated with a lower risk of and slower onset to nephrotoxicity than I-I vancomycin; however, no statistically significant difference in clinical failure rates was observed with C-I versus I-I vancomycin.