193. Comparison of Survival for MSSA and MRSA Endocarditis

Abstract

Background

Prior studies have yielded conflicting findings regarding outcomes for MRSA vs. MSSA infective endocarditis (IE). Our experience suggests that MSSA IE is not any less severe than MRSA IE. The purpose of this study was to compare survival in MSSA and MRSA IE.

Methods

Episodes of IE caused by Staphylococcus aureus were identified from the Cleveland Clinic Infective Endocarditis Registry. Only the first episode was included for each patient. Acceptance for surgery was considered surgical treatment. Survival from the surgical decision date was compared for MSSA vs. MRSA endocarditis using multivariable Cox proportional hazards regression. Selection of variables for the model was done by stepwise backward elimination from a collection of clinically important baseline variables.

Results

Between January 1, 2008 and January 1, 2010, 76 episodes of IE caused by S. aureus were identified. The mean (SD) patient age was 58 (15) years, 46 (61%) were males, 14 (18%) had a prior history of IE, 33 (43%) had diabetes mellitus, 22 (29%) had end-stage renal disease (ESRD), 27 (36%) had prosthetic valve endocarditis (PVE), 70 (92%) had left side involvement, 27 (36%) had invasive disease, 59 (78%) were referred patients, and 39 (51%) were treated surgically. The mean (SD) time to decision on surgery was 6 (7) days. Of these episodes 40 (53%) had MSSA IE and 36 (47%) had MRSA IE. There was no difference in hazard of death between MSSA and MRSA IE (HR 0.98, 95% C.I. 0.54–1.78, P-value 0.96), after adjusting for age, ESRD, prior history of IE, PVE, invasive disease, calendar year, and surgical treatment, which were the significant explanatory variables in the multivariable analysis. Survivals predicted by the model for a reference patient with MSSA IE and MRSA IE are shown in the figure.

Conclusion

Preliminary findings suggest that survival in MSSA IE may be similar to that in MRSA IE. The study is limited by its small sample size. The study finding will need confirmation with a larger sample.

Disclosures

All authors: No reported disclosures.