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A tool based on objective data to identify patients at elevated risk of hospital-onset Staphylococcus aureus bacteremia: a nested case–control study

Published online by Cambridge University Press:  07 April 2026

Richard Silvera*
Affiliation:
Medicine/Infectious Diseases, Icahn School of Medicine at Mount Sinai, New York, USA
Minji Jeon
Affiliation:
Korea University College of Medicine, Republic of Korea
Avi Ma’ayan
Affiliation:
Icahn School of Medicine at Mount Sinai, USA
Judith Aberg
Affiliation:
Medicine/Infectious Diseases, Icahn School of Medicine at Mount Sinai, New York, USA
Bernard Camins
Affiliation:
Medicine/Infectious Diseases, Icahn School of Medicine at Mount Sinai, New York, USA
Stephanie H. Factor
Affiliation:
Medicine/Infectious Diseases, Icahn School of Medicine at Mount Sinai, New York, USA
*
Corresponding author: Richard Silvera; Email: richard.silvera@mssm.edu

Abstract

Objective:

Identify patients at increased risk of hospital-onset Staphylococcus aureus (SA) bacteremia based on objective and routinely collected data on presentation to the emergency room (ER).

Design:

Nested case–control study.

Setting:

A large, inner city, tertiary care center between January 1, 2011 and August 31, 2020.

Participants:

375 cases and 2,248 matched controls.

Methods:

All hospitalized persons ≥18 years, found to have SA bacteremia at least 48 hours after admission were matched to 1–12 controls on birth year, race/ethnicity, sex, and month and year of admission. Vital signs and lab results were coded as “low” or “high” based on laboratory definitions. Multivariable models identified patient characteristics associated with an increased risk of SA bacteremia.

Results:

SA bacteremia was associated with high aspartate aminotransferase (AST) (>35 u/L )(HR = 1.92, 95%CI (1.30, 2.83), P = .001), high creatinine (Cr) (>1.1 mg/dl) (HR = 1.91, 95% CI (1.28, 2.85), P = .200), high bicarbonate (CO2) (>30 mEq/L) (HR = 2.07, 95% CI (1.17, 3.64), P = .01), and high total protein (>8.3 g/dl) (HR = 2.14, 95% CI (0.99, 4.66), P = .05). Fifteen or more days of hospital stay was associated with an increased risk of SA bacteremia (HR = 6.23, 95% CI (4.84, 8.00), P < .001).

Conclusions:

A prediction tool applied on admission of hospital stay ≥15 days OR any elevated two of the following: AST, creatinine, CO2, or total protein has sensitivity between 57%–64% and specificity to between 65%–78%.

Information

Type
Original Article
Creative Commons
Creative Common License - CCCreative Common License - BYCreative Common License - NCCreative Common License - SA
This is an Open Access article, distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike licence (https://creativecommons.org/licenses/by-nc-sa/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the same Creative Commons licence is used to distribute the re-used or adapted article and the original article is properly cited. The written permission of Cambridge University Press or the rights holder(s) must be obtained prior to any commercial use.
Copyright
© The Author(s), 2026. Published by Cambridge University Press on behalf of The Society for Healthcare Epidemiology of America
Figure 0

Table 1.Characteristics of cases and controls

Figure 1

Figure 1.Histogram of the length of stay before discharge (Controls) and the length of stay until diagnosis of staphylococcal bacteremia (Cases), Mount Sinai Hospital, Jul 1, 2011 to August 31, 2020.

Figure 2

Figure 2.Kaplan-Meier survival curve cases and controls.

Figure 3

Table 2.Three models with case (staphylococcal bacteremia) or control (no staphylococcal bacteremia) as the outcome using 3 different ways of measuring time

Figure 4

Table 3.Final model with 250 imputations combined

Figure 5

Table 4.Screening performance of different strategies on the original data set

Figure 6

Figure 3.Receiver operating characteristic curve illustrating the performance of time to infection (cases) or hospital discharge (controls) in identifying risk of staphylococcal bacteremia.

Figure 7

Figure 4.Kaplan-Meier Survival Curve comparing those identified as high risk of Staphylococcus aureus bacteremia compared to those identified as having lower risk of Staphylococcus aureus bacteremia (with missing values assumed to be normal values)†.† Patients were identified as high risk for Staphylococcus aureus bacteremia if on admission they were in still in the hospital at 15 days OR had two or more of the following on labs drawn close to the time of admission in the Emergency Room (high aspartate aminotransferase (AST), high creatinine, high carbon dioxide, and high protein).

Figure 8

Figure 5.Kaplan-Meier Survival Curve comparing those identified as high risk of Staphylococcus aureus bacteremia compared to those identified as having lower risk of Staphylococcus aureus bacteremia (with missing values assumed to be abnormal values)†.† Patients were identified as high risk for Staphylococcus aureus bacteremia if on admission they were in still in the hospital at 15 days OR had two or more of the following on labs drawn close to the time of admission in the Emergency Room (high aspartate aminotransferase (AST), high creatinine, high carbon dioxide, and high protein).

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