Rapid flu testing decreases antibiotic use
31 January 2007
Rapid influenza testing is associated with reductions in the use of
antibiotics in hospitalized adults, according to a report on Archives of
Internal Medicine (1).
New diagnostic tests are increasing the speed at which influenza and
other viral diseases are identified, according to background information in
the article. “The rapid diagnosis of influenza in hospital settings is
important for infection control and potential antiviral therapy,” the
authors write. When used in children with fevers, rapid tests for influenza
viruses were shown to reduce the use of antibiotics and other diagnostic
tests and shorten hospital stays. However, no similar studies have been done
in adults.
Ann R. Falsey, M.D., and colleagues at Rochester General Hospital and
University of Rochester School of Medicine and Dentistry, New York, reviewed
the medical records of 166 patients with documented influenza hospitalized
at their facility during four winters (1999 to 2003). Of these, 86 patients
tested positive for influenza on rapid diagnostic testing and 80 either
tested negative or did not receive the test.
Fewer patients with positive influenza test results were receiving
antibiotics (86% or 74 out of 86 patients vs. 99% or 79 of 80 patients); 12
(14%) of 86 patients with positive results discontinued antibiotics vs. 2
(2%) of 80 patients without positive test results. After the researchers
controlled for other variables, including underlying heart disease or other
conditions, a positive rapid test result was independently associated with
withholding or discontinuing antibiotic therapy.
“Although it is encouraging that antibiotic use was reduced in patients
whose rapid antigen test result was positive, 61% (27/44) of those deemed at
low risk for bacterial infection continued to receive antibiotics despite
their rapid influenza diagnosis,” the authors write. “Patients who continued
to receive antibiotics were more often older, were smokers with higher rates
of underlying chronic obstructive pulmonary disease, and had abnormal lung
examination results. These trends suggest that physicians were not
indiscriminate with their therapy but rather responding to a perceived
increased risk of bacterial infection in an older and frailer group.”
No significant differences were found between the two groups in the
number of days taking antibiotics, the length of hospital stay or
complications arising from antibiotics. Antiviral use was more common among
those with positive test results (73%, or 63 out of 86 patients) than those
with negative or no test results (8%, or six out of 80 patients).
Rapid diagnostic tests may affect not only the patient tested, but also
lead to broader benefits, such as the reduction of nosocomial
(hospital-acquired) influenza. “Given the environment of increasingly severe
antibiotic-resistant nosocomial infections, control of inappropriate
antibiotic use is highly desirable,” the authors write. “With ever more
sophisticated tools … rapid accurate diagnosis for a wide number of viral
pathogens will become available in the near future. To optimize use of these
new diagnostic tools and limit antibiotic use in patients with viral
infection, more accurate methods of diagnosing concomitant bacterial
infections are needed.”
1. Ann R. Falsey, MD; Yoshihiko Murata, MD, PhD; Edward
E. Walsh, MD. Impact of Rapid Diagnosis on Management of Adults
Hospitalized With Influenza. Arch Intern Med. 2007;167.
The full article is available on The Archives of Internal Medicine
website:
http://archinte.ama-assn.org/cgi/content/full/167.4.ioi60207
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