A new simplified predictive model for mortality in methicillin-resistant Staphylococcus aureus bacteremia
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Adjustment for confounding is important in observational methicillin-resistant Staphylococcus aureus bacteremia (MRSAB) studies due to the wide spectrum of disease severity and baseline health status that patients present with. The objectives of this study were to develop a simplified MRSAB-specific scoring model to estimate the risk of 30-day all-cause mortality and to compare its performance to the APACHE II and Pitt Bacteremia scores. Retrospective, singe-center, cohort study in adults with MRSAB 2008 to 2018. Independent predictors of mortality were identified through multivariable logistic regression. A scoring model was derived using a regression coefficient-based scoring method. Discriminatory ability was assessed using the c statistic. A total of 455 patients were included. Thirty-day mortality was 16.3%. The MRSAB score consisted of six variables: age, respiratory rate, Glasgow Coma scale, renal failure, hospital-acquired MRSAB, and infective endocarditis or lower respiratory tract infection source. The score demonstrated very good discrimination (c statistic 0.8662, 95% CI 0.824–0.909) and was superior to the APACHE II (P = 0.043) and the Pitt bacteremia (P < 0.001) scores. A weighted combination of six independent variables routinely measured in patients with MRSAB can be used to predict, with high discrimination, 30-day all-cause mortality. External validation is required before widespread use.
KeywordsMethicillin-resistant Staphylococcus aureus Bacteremia Risk stratification APACHE II Pitt bacteremia score
This study was presented, in part, at IDWeek 2018, October 5, 2018, San Francisco, CA, USA; abstracts 1061 and 1227.
This study was carried out as part of the authors’ routine work with no external funding.
Compliance with ethical standards
Conflict of interest
MJR has received funding support, consulted or participated in speaking bureaus for Allergan, Achaogen, Bayer, Melinta, Merck, Theravance, The Medicine Company, Sunovian and Zavante, and NIAID (all unrelated to this study). SCJJ, AML, and SB have nothing to declare.
This study was approved by the Wayne State University Institutional Review Board (IRB# 122916MP2E) and the Detroit Medical Center Research Committee (14081) with a waiver for informed consent.
Due to the retrospective nature of this study, informed consent was not required.
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