Comparative Effectiveness of Vancomycin versus Early Daptomycin for MRSA Bacteremia with Vancomycin MIC >1 mg/L: A Multicenter Evaluation
Methods: We conducted a retrospective, nationwide, multicenter, matched (by age, bacteremia type, severity of illness, ID consult and institution), cohort study that compared daptomycin versus vancomycin among adult patients with MRSA bacteremia with high vancomycin MICs (1.5-2 mg/L). The primary outcome was composite failure, defined as having: 60-day all-cause mortality, 7-day clinical or microbiological failure, failure at end of therapy, and/or 30-day BSI relapse. Secondary outcomes included early bacteremia clearance by day 4 without recurrence and acute kidney injury (AKI). Stratified treatment-outcomes analyses by key baseline covariates were performed.
Results: One hundred seventy patients from 11 United States institutions were included. The median daptomycin dose was 6 mg/kg (interquartile, IQ, range, 6-8 mg/kg). Daptomycin was dosed >8 mg/kg in 26% (22/85). All patients had vancomycin troughs of at least 10 mg/L (median 17.5 mg/L; IQ range, 14.0-22.0 mg/L). Vancomycin troughs were >15 mg/L in 71% (60/85). The primary composite endpoint did not vary between the daptomycin and vancomycin groups (31% vs. 39%, respectively, P = 0.259). Both end of therapy failure and acute kidney injury were significantly lower in the daptomycin relative to the vancomycin group (11% vs 24%, respectively, P = 0.025, and 9% vs 23%, respectively, P = 0.043). In the stratified analyses, daptomycin demonstrated a higher rate of bacteremia clearance by day 4 than vancomycin (94% vs 56%, respectively, P = 0.035) among immunocompromised patients (n=26).
Conclusion: Results from this multicenter study provide real-world comparative data on the outcomes with daptomycin vs vancomycin in adult patients with MRSA bacteremia with vancomycin MIC 1.5-2 mg/L. As with all observational studies, these findings should be interpreted cautiously.
Cubist: Employee and Shareholder, Salary
A. Wong-Beringer, None
J. Bensman, None
K. Lamp, Cubist Pharmaceuticals: Employee and Shareholder, Salary
W. J. Smith, None
K. Bauer, None
D. Goff, None
R. Adamson, None
K. Leuthner, None
M. Virata, None
J. A. Mckinnell, None
S. B. Chaudhry, None
R. Eskandarian, None
T. Lodise, Cubist Pharmaceuticals: Consultant, Consulting fee
K. Reyes, None
M. Zervos, None