Propensity Matched Analysis of Early Daptomycin versus Vancomycin for Methicillin-Resistant S. aureus Bloodstream Infections: Daptomycin Improves Outcomes Regardless of Vancomycin MIC.
Antimicrob Agents Chemother. 2016 Jul 18;
Authors: Claeys KC, Zasowski EJ, Casapao AM, Lagnf AM, Nagel JL, Nguyen CT, Hallesy JA, Compton MT, Kaye KS, Levine DP, Davis SL, Rybak MJ
INTRODUCTION: Vancomycin remains the mainstay treatment for MRSA bloodstream infections (BSIs) despite increased treatment failures. Daptomycin has been shown to improve clinical outcomes in MRSA BSI with vancomycin MICs > 1 mg/L, but these studies relied on automated susceptibility testing. We evaluated outcomes of MRSA BSI with vancomycin MIC determined by standard broth microdilution (BMD).
METHODS: Retrospective, matched cohort of MRSA BSI patients treated with vancomycin or daptomycin from January 2010 to March 2015. Patients were matched using propensity-adjusted logistic regression, which included: age, Pitt Bacteremia Score, primary BSI source, and hospital of care. The primary endpoint was clinical failure, which was a composite endpoint of the following metrics: 30-day mortality, bacteremia ≥ 7days, or change in MRSA therapy due to persistent/worsening signs/symptoms. Secondary endpoints included MRSA-attributable mortality and days of bacteremia. Independent predictors of failure were determined through conditional backwards-stepwise logistic regression, with vancomycin BMD MIC forced into the model.
RESULTS: 262 patients were matched. Clinical failure was significantly higher in the vancomycin cohort (45.0% vs. 29.0%, p = 0.007). All-cause 30-day mortality was significantly higher in the vancomycin cohort (15.3% vs. 6.1%, p = 0.024). These outcomes remained significant when stratified by vancomycin BMD MIC. There was no significant difference in length of bacteremia. Variables independently associated with treatment failure included vancomycin therapy (aOR = 2.16, 95% CI = 1.24 - 3.76), intensive care (aOR = 2.46, 95% CI = 1.34 - 4.54) or primary source infective endocarditis (aOR = 2.33, 95% CI = 1.16 - 4.68) CONCLUSIONS: Treatment of MRSA BSI with daptomycin was associated with reduced clinical failure and 30-day mortality; this finding was independent of vancomycin BMD MIC.
PMID: 27431221 [PubMed - as supplied by publisher]