Effects of Local Variation, Specialty, and Beliefs on Antiviral Prescribing for Influenza
BRIEF REPORT • CID
Effects of Local Variation, Specialty, and Beliefs on Antiviral Prescribing for Influenza
Michael B. Rothberg 0 1 3 4
Aleta B. Bonner 1 3 5
M. Hasan Rajab 1 3 5 6
Hyun Sun Kim 1 3 6
Barbara W. Stechenberg 1 2 3
David N. Rose 0 1 3 4
0 Tufts University School of Medicine , Boston, Massachusetts , and the Departments of
1 Received 16 June 2005; accepted 2 September 2005; electronically published 18 November 2005. Baystate Medical Center , 759 Chestnut St., Springfield, MA 01199 (Michael. Rothberg @bhs.org). Clinical Infectious Diseases 2006; 42:95-9 2005 by the Infectious Diseases Society of America. All rights reserved. 1058-4838/2006/4201-0015$15.00
2 Division of Pediatric Infectious Diseases, Department of Pediatrics, Baystate Medical Center , Springfield
3 In 2004, we conducted a survey of physician knowledge, at- titudes, and practices regarding influenza diagnosis and treatment at Baystate Medical Center in Massachusetts and Scott & White Hospital and Clinic in Texas. Of the 579 phy- sicians we contacted, 336 completed the survey. Sixty-one percent of the respondents prescribed antivirals, and 62% used rapid testing. Prescribing practices were associated with location, practice size, use of rapid testing, and belief in the efficacy of antivirals
4 Division of General Medicine and Geriatrics, Department of Medicine
5 Texas A&M University College of Medicine , Temple, Texas
6 Biostatistics, Scott and White Hospital
Although influenza strikes 5%-20% of the population each year , little is known about physicians' approaches to this common illness. Randomized trials have demonstrated the efficacy of anti-influenza drugs in shortening the course of influenza infection and in preventing secondary infections that require antibiotics, but the effects of antiviral therapy on the rates of hospitalization and mortality are less-well documented . In addition, there are limited data on children, high-risk patients, and elderly patients. In October 2004, during a vaccine shortage, the Centers for Disease Control and Prevention  issued interim antiviral guidelines, which recommended that high-risk patients receive amantadine or rimantadine for chemoprophylaxis and oseltamivir or zanamivir for treatment. The recommendations for other patients are vague, and diagnosis is not addressed.
tices regarding influenza testing and treatment. Anonymity was
assured, and completion of the survey implied informed
consent. The study was closed on 15 June 2004. The study was
approved by the institutional review boards of both Baystate
Medical Center and Scott & White Hospital.
The data were entered automatically in an electronic database
by the Internet survey company SurveyMonkey.com, then
downloaded with SAS software version 8.2 (SAS Institute).
Patient demographic variables were compared using the x2 test
or Fisher’s exact test, as appropriate. The association of main
study variables with prescription of antivirals were assessed with
logistic regression models and backward variable selection
Results. Three hundred and thirty-six physicians (176 from
Massachusetts and 160 from Texas) completed the survey
(response rate, 58%). There were significant demographic and
clinical differences between physicians in Massachusetts and
those in Texas (table 1).
Sixty-one percent of the respondents reported that they had
prescribed antiviral therapy during the past year, and 32% had
written 15 prescriptions. Factors associated with the decision
to prescribe or not prescribe antiviral drugs appear in table 2.
Seventy-six percent of respondents in Texas reported
prescribing antiviral therapy at least once in the past year, and 50%
had written 15 prescriptions. In Massachusetts, however, only
48% had ever prescribed antiviral therapy (P ! .0001). Internists
comprised the lowest proportion of prescribers (48%), and
family practitioners, the highest (84%).
In a multivariate analysis, the following factors were
associated with prescribing antivirals: location (Texas vs.
Massachusetts; OR, 3.5; 95% CI, 2.2–5.9), higher patient volume (OR,
2.0; 95% CI, 1.5–2.6), use of rapid testing (OR, 1.8; 95% CI,
1.1–3.0), and the beliefs that antiviral therapy shortens illness
(OR, 4.9; 95% CI, 1.8–13.2) and decreases mortality rates (OR,
3.0; 95% CI, 1.7–5.5).
Respondents who indicated they had not prescribed any
antiviral therapy offered several reasons for not prescribing (figure
1). The reasons did not differ significantly by location. No one
cited concern about inducing antiviral resistance.
Discussion. Although effective antiviral therapy for
influenza has been available for almost 40 years, widespread
prevention strategies have focused on vaccination, and little is
known about physicians’ use of antiviral medications to treat
influenza. This is the first study to assess physicians’ reported
prescribing of anti-influenza therapy and the possible
determinants of prescribing in the absence of any published
guidelines or specific recommendations. In a multivariate analysis,
we found that location, practice size, the performance of rapid
testing, and the beliefs that antiviral therapy shortens the course
of illness and decreases mortality all predicted the prescription
Table 1. Demographic information and responses of survey
participants, by location.
No. (%) of
NOTE. MA, Massachusetts; TX, Texas.
We assessed physician beliefs about antiviral effectiveness
because we thought that belief in the effectiveness of antivirals
would lead to prescription of antivirals. Although 87% of
respondents in our study correctly identified that the medications
shorten the course of illness, only 28% knew that they prevent
bacterial complications. On the other hand, 29% believed that
antiviral therapy decreases mortality, despite a lack of evidence.
Not surprisingly, the belief that antiviral medications prevented
serious complications was linked to antiviral prescribing.
However, divergent beliefs about effectiveness explained only a small
part of the variation in practice. Physicians in Massachusetts
and Texas held similar beliefs about antiviral efficacy and gave
the same reasons for not prescribing antiviral therapy, yet
practice varied widely between the 2 locations. We hypothesized
that antiviral prescribing would be more common in Texas due
No. (%) of respondents
(n p 336)
to the severity of the 2003–2004 influenza epidemic in that
state, and our hypothesis was borne out in both univariate and
Most physicians who did not prescribe antiviral therapy
reported that patients presented too late for treatment. If that is
the case, it may be that physicians have failed to properly
educate patients about influenza. Because many patients feel they
should not seek medical attention until they have had several
days of fever, they miss the opportunity to be treated with
specific therapy, which reinforces the behavior of not seeking
medical attention for influenza symptoms. It may be time,
especially for high-risk patients, to reconsider this behavior.
More troubling is the opinion, held by 40% of respondents,
that influenza is self-limited and does not require treatment.
Among high-risk patients, even those who have been
vaccinated, the rate of secondary bacterial pneumonia after influenza
infection is high. The appropriate use of antiviral therapy in
this group could decrease the number of both lower respiratory
tract complications and hospitalizations . Finally, physicians
expressed concern about cost. Several analyses have addressed
the cost-effectiveness of antiviral therapy in different
populations and have come to the conclusion that in most
circumstances it is cost-effective [2, 6, 10–12].
Our study had some limitations. The retrospective nature of
the study may have introduced recall bias. The anonymity of
the survey precluded the analysis of nonresponders’ beliefs and
practices, and although our response rate was high, it is possible
that inclusion of data from those who chose not to respond
could have altered our results. Finally, our study population
was limited to 2 medical centers that may not be representative
either of their regions or of the nation as a whole. Nevertheless,
we demonstrate wide variation in practice that cannot be
ascribed to chance.
Anti-influenza therapy could decrease the substantial
morbidity associated with annual influenza epidemics. Despite this,
a large proportion of physicians fail to prescribe these agents.
On the basis of the responses of nonprescribers, it appears that
better education of providers about influenza and antiviral
therapy, coupled with education of patients that would encourage
presentation within the 48-h treatment “window,” could
increase the rate of influenza treatment in the outpatient setting.
The Centers for Disease Control and Prevention’s interim
guidelines  may ameliorate this situation, but they may not
be renewed this season. In addition, these guidelines are vague
about the use of antivirals for average-risk patients, do not
address diagnosis, and do not provide documentation to
support the recommendations. Given the prevalence of and severity
of influenza and the wide range of beliefs and practices
regarding treatment, detailed and well-documented practice
guidelines are needed.
Potential conflicts of interest. M.R. has served as a consultant to
Quidel; A.B. has served as a consultant to Quidel and Biostar, and has received
grant support from Binax. All other authors: no conflicts.
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