Several factors, including older age, residence in a
nursing home and severe bacteremia, were associated with increased risk for
death among patients with methicillin-resistant Staphylococcus aureus,
researchers suggest.
In a retrospective cohort study, researchers from the
Rockefeller University, Mount Sinai School of Medicine and Weill Cornell School
of Medicine analyzed predictors for risk of death among patients with MRSA in
an academic medical center from 2002 to 2007. The study included 699 episodes
of MRSA among 603 patients. The researchers obtained patient information from
electronic and paper charts of these patients.
The patients had an average length of stay of 32.9 days,
and many of the cases occurred in patients with renal insufficiency or
cardiovascular disease. More than 40% of patients had recently had a surgical
procedure and 43% of the cases were secondary to infections related to central
venous catheters. The 90-day all-cause mortality rate was 27.2%.
Fifty-five of the 699 episodes were caused by a
vancomycin-intermediate resistant S. aureus strain and 55 of the
episodes were caused by a heteroresistant vancomycin-intermediate resistant
S. aureus strain. Among the patients, 47% had been exposed to
vancomycin, and of these, 60% had a prior MRSA infection. Vancomycin was used
to treat 81% of the 699 MRSA episodes.
Cirrhosis of the liver and central venous catheter
infections were associated with a nearly doubled risk for heteroresistant
vancomycin-intermediate resistant S. aureus infection. A history of
vancomycin exposure increased the risk for vancomycin-intermediate resistant
S. aureus.
The following factors were independently associated with
increased risk for death: older age, cirrhosis, renal insufficiency, living in
a nursing home or admission to the ICU. There was a lower risk for death among
patients who had diabetes or who consulted with an infectious diseases
specialist.
“Our study emphasizes that after a diagnosis of
MRSA bacteremia is made, it is crucial to determine patient risk factors and
not just the vancomycin MIC for the infecting strain,” the researchers
wrote. “The consequences of MRSA bacteremia are clear — many patients
will die or experience a decline from their baseline clinical condition.”
References:
Pastagia M. Emerg Infect Dis. 2012;published online ahead of
print June 13.
Disclosures:
The researchers report no relevant financial disclosures.