1227. Development of a Clinical Prediction Model for Mortality in Methicillin-Resistant Staphylococcus aureus Bacteremia
Session: Poster Abstract Session: Healthcare Epidemiology: MSSA, MRSA and Other Gram Positive Infections
Friday, October 5, 2018
Room: S Poster Hall
Background:

Methicillin-resistant Staphylococcus aureus bloodstream infection (MRSA BSI) is associated with high mortality despite advances in medical care. Mortality prediction may have a profound impact on clinical decision making and risk stratification. Widely used scoring systems such as the Acute Physiology and Chronic Health Evaluation (APACHE) II Score and the Pitt Bacteremia Score were derived in the general critical care and Gram-negative BSI populations, respectively and may be less precise in MRSA BSI. We sought to develop a predictive model (PM) for 30-d mortality in patients with MRSA BSI based on characteristics readily assessable at initial evaluation.

Methods:

Retrospective, singe-center, cohort study in adults with MRSA BSI 2008 to 2018. Patients who did not receive active therapy within 72 h of index culture were excluded. Independent baseline demographic, clinical and infection predictors of 30-d mortality were identified through multivariable logistic regression analysis with bootstrap resampling and coefficient shrinkage. The PM was derived using a regression coefficient-based scoring method. PM discriminatory ability was assessed using the c-statistic. The optimal threshold score was determined using the Youden Index (J).

Results:

A total of 455 patients were included and 30-d mortality was 16.3%. The PM consisted of 5 variables and a potential total score of 33. Points were assigned as follows: age (9 points ≥ 90 y, 6 points 80 – 89 y, 5 points 70 – 79 y, 0 points < 70 y); Glasgow Coma Scale (8 points ≤ 9, 5 points 10 – 13, 0 points ≥ 14); 7 points infective endocarditis or pneumonia; 5 points serum creatinine ≥ 3.5 dl/L; and 4 points respiratory rate < 10 or > 24. The PM c-statistic was 0.860 (95% CI 0.818, 0.902). The PM score with the maximum J value was 13. Thirty-d mortality was 5.2% vs. 44.5% for PM score <13 vs. ≥ 13 points, respectively (P < 0.001). The sensitivity, specificity, positive predictive value (PV), negative PV and accuracy using a threshold of 13 points were 77.0%, 81.4%, 44.5%, 94.8%, and 80.7%, respectively.

Conclusion:

Our findings demonstrate a weighted combination of 5 independent variables readily assessable at initial evaluation can be used to predict, with high discrimination, 30-d mortality in MRSA BSI. External validation is required before wide-spread clinical use.

Sarah Jorgensen, PharmD, BCPS, AAHIVP1, Evan J. Zasowski, PharmD, MPH2,3, Trang D. Trinh, PharmD, MPH4, Abdalhamid M. Lagnf, MPH1, Sahil Bhatia, B.S.1 and Michael J. Rybak, PharmD, MPH, PhD5, (1)Anti-Infective Research Laboratory, Department of Pharmacy Practice, Wayne State University, Eugene Applebaum College of Pharmacy & Health Sciences, Detroit, MI, (2)Anti-Infective Research Laboratory, College of Pharmacy, School of Medicine, Division of Infectious Diseases, Wayne State University, Detroit, MI, (3)Department of Pharmacy Practice and Translational Research, University of Houston College of Pharmacy, Houston, TX, (4)Department of Clinical Pharmacy, University of California, San Francisco, School of Pharmacy, San Francisco, CA, (5)259 Mack Ave, Suit 4131, Eugene Applebaum College of Pharmacy and Health Sciences Bldg, 259 Mack Ave, Detroit, MI

Disclosures:

S. Jorgensen, None

E. J. Zasowski, None

T. D. Trinh, None

A. M. Lagnf, None

S. Bhatia, None

M. J. Rybak, Allergan: Consultant , Grant Investigator and Speaker's Bureau , Research grant and Research support . Achaogen: Consultant , Grant Investigator and Speaker's Bureau , Consulting fee , Research grant and Research support . Bayer: Consultant , Grant Investigator and Speaker's Bureau , Consulting fee , Research grant and Research support . Melinta: Consultant , Grant Investigator and Speaker's Bureau , Consulting fee , Research grant and Research support . Merck: Consultant , Grant Investigator and Speaker's Bureau , Consulting fee , Research grant and Research support . Theravance: Consultant , Grant Investigator and Speaker's Bureau , Consulting fee , Research grant and Research support . Sunovian: Consultant , Grant Investigator and Speaker's Bureau , Consulting fee , Research grant and Research support . Zavante: Consultant , Grant Investigator and Speaker's Bureau , Consulting fee , Research grant and Research support . NIAID: Consultant , Grant Investigator and Speaker's Bureau , Consulting fee , Research grant and Research support .

Findings in the abstracts are embargoed until 12:01 a.m. PDT, Wednesday Oct. 3rd with the exception of research findings presented at the IDWeek press conferences.