Mike the Mad Biologist

I’m Famous!!

Well, kinda sorta. I’m mentioned in a UPI article about rapid diagnosis of influenza and antibiotic use. Rather than repeat the UPI story, here’s the abstract (don’t worry, I’ll translate):

Background: Rapid influenza testing decreases antibiotic and ancillary test use in febrile children, yet its effect on the care of hospitalized adults is unexplored.We compared the clinical management of patients with influenza whose rapid antigen test result was positive (Ag+) with the management of those whose rapid antigen test result was negative or the test was not performed (Ag0).

Methods: Medical record review was performed on patients with influenza hospitalized during 4 winters (1999-2003). Hospital policy mandated influenza testing (antigen or culture) for all patients with acute cardiopulmonary diseases admitted from November 15 through April 15. A subset of patients participated in an epidemiological study and had reverse-transcriptase polymerase chain reaction or serologic testing performed. Clinical data from Ag+ and Ag0 patients were compared.

Results: Of 166 patients with available records, 86 were Ag+ and 80 were Ag0. Antibiotic use (74 [86%] of 86 patients vs 79 [99%] of 80 patients; P = .002) was less and antibiotic discontinuance (12 [14%] of 86 patients vs 2 [2%] of 80 patients; P=.01) was greater in Ag+ compared with Ag0 patients. No significant differences in antibiotic days, length of hospital stay, or antibiotic complications were noted. Antiviral use (63 [73%] of 86 patients vs 6 [8%] of 80 patients; P<.001) was greater in Ag+ than Ag0 patients. Antigen status was independently associated with withholding or discontinuing antibiotics in multivariate analysis. Of 44 Ag+ patients deemed low risk for bacterial infection, 27 continued to receive antibiotics despite positive influenza test results. These patients more commonly had pulmonary disease and had significantly more abnormal lung examination results (P = .005) compared with those in whom antibiotics were withheld or discontinued.

Conclusions: Rapid influenza testing leads to reductions in antibiotic use in hospitalized adults. Better tools to rule out concomitant bacterial infection are needed to optimize the impact of viral testing.

What the study was examining was the effect a simple and rapid diagnostic test for influenza would have on antibiotic use in hospitalized influenza patients. Often, when a patient is brought in with fever and severe respiratory problems, it’s difficult to determine whether the cause is viral, such as influenza, or bacterial [link], so patients are started on antibiotics (that’s not irresponsible; remember that the infection is severe enough to require hospitalization). In the study, the researchers found that patients with a positive result (i.e., had influenza) were only given antibiotics 86% of the time versus patients with a negative result who received antibiotics 99% of time. Also, antivirals were used more responsibly: 73% of influenza-positive patients received an antiviral, whereas those that tested negative only received antivirals in eight percent of cases.

Well, the good news is that antibiotics (and antivirals) are being used appropriately: in the influenza cases, doctors claimed that they prescribed antibiotics to their high-risk patients to prevent secondary infections. No doctors reported prescribing due to pressure from patients or family members. What is disturbing, however, is that in four percent of cases, doctors felt they had to prescribe antibiotics in order to justify hospitalization (but, no, our healthcare system isn’t fubar. Not at all).

But enough about the article. Let’s talk about me. When I spoke to the UPI reporter, the point I was trying to make, and which was shrunk to incoherence by the editor, is that the best way to avoid the problem of using antibiotics to treat secondary bacterial infections is to avoid the primary influenza infection. To do that, we need a better vaccination strategy; actually, we need a vaccination strategy. I’m not sure that got through in the UPI story.


  1. #1 Michael Schmidt
    January 24, 2007

    Well, as a pain-in-the-ass inorganic chemist, I must object to your use of Ag+ for a positive antigen test. It’s the most common ion of silver!

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