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Original Investigation
February 17, 2020

Empirical Anti-MRSA vs Standard Antibiotic Therapy and Risk of 30-Day Mortality in Patients Hospitalized for Pneumonia

Author Affiliations
  • 1Division of Pulmonary and Critical Care, Veterans Affairs Salt Lake City Health Care System, Salt Lake City, Utah
  • 2University of Utah, Salt Lake City
  • 3Division of Epidemiology, University of Utah, Salt Lake City
  • 4Division of Epidemiology, Veterans Affairs Salt Lake City Health Care System, Salt Lake City, Utah
  • 5Division of Internal Medicine, University of Utah, Salt Lake City
  • 6Department of Health Economics and Epidemiology, Veterans Affairs Salt Lake City Health Care System, Salt Lake City, Utah
  • 7Department of Internal Medicine, Veterans Affairs Salt Lake City Health Care System, Salt Lake City, Utah
  • 8Division of Infectious Disease, Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California
JAMA Intern Med. 2020;180(4):552-560. doi:10.1001/jamainternmed.2019.7495
Key Points

Question  What is the association of empirical anti–methicillin-resistant Staphylococcus aureus therapy with 30-day mortality for patients hospitalized with pneumonia?

Findings  This national cohort study of 88 605 hospitalizations for pneumonia that used detailed clinical data to emulate a clinical trial did not find a mortality benefit of empirical anti–methicillin-resistant S aureus therapy vs standard antibiotics for any group of patients examined, even those with risk factors for methicillin-resistant S aureus.

Meaning  This study contributes to a growing body of evidence suggesting that empirical anti–methicillin-resistant S aureus therapy using existing risk approaches may not be beneficial to most patients hospitalized with pneumonia.

Abstract

Importance  Use of empirical broad-spectrum antibiotics for pneumonia has increased owing to concern for resistant organisms, including methicillin-resistant Staphylococcus aureus (MRSA). The association of empirical anti-MRSA therapy with outcomes among patients with pneumonia is unknown, even for high-risk patients.

Objective  To compare 30-day mortality among patients hospitalized for pneumonia receiving empirical anti-MRSA therapy vs standard empirical antibiotic regimens.

Design, Setting, and Participants  Retrospective multicenter cohort study was conducted of all hospitalizations in which patients received either anti-MRSA or standard therapy for community-onset pneumonia in the Veterans Health Administration health care system from January 1, 2008, to December 31, 2013. Subgroups of patients analyzed were those with initial intensive care unit admission, MRSA risk factors, positive results of a MRSA surveillance test, and positive results of a MRSA admission culture. Primary analysis was an inverse probability of treatment–weighted propensity score analysis using generalized estimating equation regression; secondary analyses included an instrumental variable analysis. Statistical analysis was conducted from June 14 to November 20, 2019.

Exposures  Empirical anti-MRSA therapy plus standard pneumonia therapy vs standard therapy alone within the first day of hospitalization.

Main Outcomes and Measures  Risk of 30-day all-cause mortality after adjustment for patient comorbidities, vital signs, and laboratory results. Secondary outcomes included the development of kidney injury and secondary infections with Clostridioides difficile, vancomycin-resistant Enterococcus species, or gram-negative bacilli.

Results  Among 88 605 hospitalized patients (86 851 men; median age, 70 years [interquartile range, 62-81 years]), empirical anti-MRSA therapy was administered to 33 632 (38%); 8929 patients (10%) died within 30 days. Compared with standard therapy alone, in weighted propensity score analysis, empirical anti-MRSA therapy plus standard therapy was significantly associated with an increased adjusted risk of death (adjusted risk ratio [aRR], 1.4 [95% CI, 1.3-1.5]), kidney injury (aRR, 1.4 [95% CI, 1.3-1.5]), and secondary C difficile infections (aRR, 1.6 [95% CI, 1.3-1.9]), vancomycin-resistant Enterococcus spp infections (aRR, 1.6 [95% CI, 1.0-2.3]), and secondary gram-negative rod infections (aRR, 1.5 [95% CI, 1.2-1.8]). Similar associations between anti-MRSA therapy use and 30-day mortality were found by instrumental variable analysis (aRR, 1.6 [95% CI, 1.4-1.9]) and among patients admitted to the intensive care unit (aRR, 1.3 [95% CI, 1.2-1.5]), those with a high risk for MRSA (aRR, 1.2 [95% CI, 1.1-1.4]), and those with MRSA detected on surveillance testing (aRR, 1.6 [95% CI, 1.3-1.9]). No significant favorable association was found between empirical anti-MRSA therapy and death among patients with MRSA detected on culture (aRR, 1.1 [95% CI, 0.8-1.4]).

Conclusions and Relevance  This study suggests that empirical anti-MRSA therapy was not associated with reduced mortality for any group of patients hospitalized for pneumonia. These results contribute to a growing body of evidence that questions the value of empirical use of anti-MRSA therapy using existing risk approaches.

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    1 Comment for this article
    EXPAND ALL
    RE: Empirical Anti-MRSA vs Standard Antibiotic Therapy and Risk of 30-Day Mortality in Patients Hospitalized for Pneumonia
    Rajiv Kumar, MBBS, MD. | Faculty, Dept. of Pharmacology, Government Medical College & Hospital, Chandigarh, 160030. India.
    The authors rightly mentioned that empirical anti-MRSA antibiotic therapy was not supported in previous studies and this study also confirms the same.

    Although the Infectious Diseases Society of America and the American Thoracic Society have guidelines for the management of pneumonia / community-acquired pneumonia,  it is all about careful, judicious and rational use of antibiotics.

    The decision to use empirical anti-MRSA or standard antibiotics  depends on clinical judgment, and it varies from patient to patient.
     
    It is essential for physicians and other clinicians to promote respiratory hygiene measures and cough etiquette
    to reduce transmission of respiratory infections in patients and for good clinical recovery.

    Regards,

    Dr.Rajiv Kumar, Dr.Sangeeta Bhanwra. Faculty Dept. of Pharmacology, Government Medical College & Hospital, Chandigarh, 160030. India.

    DRrajiv.08@gmail.com
    CONFLICT OF INTEREST: None Reported
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