Rapid Flu Test Cuts Antibiotic Use in Adults

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Rapid Flu Test Cuts Antibiotic Use in Adults

 

By Michael Smith, Senior Staff Writer, MedPage Today

Reviewed by Zalman S. Agus, MD; Emeritus Professor at the University of

Pennsylvania School of Medicine.

January 22, 2007

 

 

Action Points

 

* Explain to interested patients that as a virus, influenza is not affected

by antibiotics, yet antibiotics are often prescribed for patients suffering

from the flu.

* Point out that this study suggests that rapid flu tests reduce the

inappropriate use of antibiotics in adults, paralleling studies that have shown

a

similar reduction in children.

 

 

 

 

ROCHESTER, N.Y., Jan. 22 -- When a rapid test catches the flu, it reduces

inappropriate use of antibiotics in adults, according to researchers here.

 

The rapid test -- with results available in minutes -- has already been

shown to reduce antibiotic use among children, according to Ann Falsey, M.D.,

of

the University of Rochester Medical Center and Rochester General Hospital.

 

 

Now a retrospective chart review of four flu seasons at the hospital shows a

similar pattern for adults, Dr. Halsey and colleagues reported online today

in the Archives of Internal Medicine.

 

 

" I was pleasantly surprised by the results, " Dr. Falsey said. " Rapid testing

does give physicians evidence to discontinue antibiotics, and some

physicians are responding to the evidence. "

 

 

The report will appear in the Feb. 26 issue, but it was released to

journalists early because of its public health importance.

 

 

During the winters of 1999 through 2003, the hospital conducted influenza

testing - either with the rapid test or through culture -- for all patients

with acute cardiopulmonary diseases admitted from Nov. 15 through April 15.

 

 

Of 166 patients with documented influenza, the researchers reported, 86 were

positive on the rapid test (Ag+) and 80 were either negative or did not have

the rapid test performed (Ag0).

 

 

Analysis of the groups found:

 

 

* Antibiotics were used in 74 of the 86 Ag+ patients (86%), compared with 79

of 80 Ag0 patients (99%). The difference was statistically significant at

P=0.002.

* Antibiotics were stopped in 12 Ag+ 86 patients (14%), compared with two

of the Ag0 patients (2%). The difference was significant at P=0.01.

* Antiviral use was greater in the Ag+ patients -- 73% versus 8% -- which

was significant at P<0.001.

 

 

Interestingly, however, among the 44 Ag+ patients who were thought to be at

low risk for bacterial infection, 27 continued to receive antibiotics despite

positive rapid flu tests, Dr. Halsey and colleagues found.

 

 

These patients tended to be older, to be smokers, and to have pulmonary

disease. They also had significantly more abnormal lung exams compared with

those

in whom antibiotics were withheld or discontinued.

 

 

The antibiotic treatment, Dr. Falsey said, probably occurred as a

pre-emptive strike because physicians were worried about a concomitant

bacterial

infection in these patients. Further research is needed to assess rates of

concomitant bacterial infection during viral respiratory illness and to develop

accurate methods for distinguishing viral from bacterial processes, they noted.

 

 

" Doctors are trying to do the right thing by their patients, " she said.

" Sometimes they perceive antibiotics as the safest choice, even though a virus

may be the cause of their patient's illness. "

 

 

The researchers noted the study was limited by its retrospective nature, in

that the different clinical characteristics of the groups contributed to

variations in management.

 

 

On the other hand, multivariate analysis showed that rapid test status was

significantly associated with antibiotic use, " providing evidence that the

test results were affecting management, " they said.

 

This study was supported by a grant from the National Institutes of Health.

Dr. Falsey serves on the advisory board for Quidel Inc., of San Diego, which

makes rapid diagnostic test.

 

 

 

Primary source: Archives of Internal Medicine

Source reference:

Falsey AR et al. " Impact of Rapid Diagnosis on Management of Adults

Hospitalized With Influenza. " Arch Intern Med

2007;167:(doi:10.1001/archinternmed.167.4.ioi60207).

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http://www.medpagetoday.com/InfectiousDisease/URItheFlu/tb/4902