Effects of Local Variation, Specialty, and Beliefs on Antiviral Prescribing for Influenza

Clinical Infectious Diseases, Jan 2006

In 2004, we conducted a survey of physician knowledge, attitudes, and practices regarding influenza diagnosis and treatment at Baystate Medical Center in Massachusetts and Scott & White Hospital and Clinic in Texas. of the 579 physicians 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.

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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 [1], 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 [2]. 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 [3] 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 technique. 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 of antivirals. Table 1. Demographic information and responses of survey participants, by location. Specialty Pediatrics No. (%) of respondents 84 (48) 92 (52) 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 Overall (n p 336) Variables Texas Massachusetts Specialty 39 (24) 92 (52) 72 (35) 56 (47) 48 (33) 83 (44) to the severity of the 2003–2004 influenza epidemic in that state, and our hypothesis was borne out in both univariate and multivariate analyses. 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 [9]. 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 [3] 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. Acknowledgments 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. of the rapid diagnosis of influenza on physician decision-making and patient management in the pediatric emergency department: results of a randomized, prospective, controlled trial. Pediatrics 2003; 112:363–7. 6. Smith KJ, Roberts MS. Cost-effectiveness of newer treatment strategies for influenza. Am J Med 2002; 113:300–7. 7. Rothberg MB, He S, Rose DN. Management of influenza symptoms in healthy adults. J Gen Intern Med 2003; 18:808–15. 8. Centers for Disease Control and Prevention. Update: influenza activity—United States and worldwide, 2003–04 season, and composition of the 2004–05 influenza vaccine. MMWR Morb Mortal Wkly Rep 2004; 53:547–52. 9. Kaiser L, Wat C, Mills T, Mahoney P, Ward P, Hayden F. Impact of oseltamivir treatment on influenza-related lower respiratory tract 1. Nicholson KG , Wood JM , Zambon M. Influenza . Lancet 2003 ; 362 : 1733 - 45 . 2. Turner D , Wailoo A , Nicholson K , et al. Systematic review and economic decision modelling for the prevention and treatment of influenza A and B. Health Technol Assess 2003 ; 7:iii-iv , xi-xiii, 1 - 170 . 3. Centers for Disease Control and Prevention. Influenza antiviral medications: 2004-05 interim chemoprophylaxis and treatment guidelines . Centers for Disease Control and Prevention , 2004 . Available at: http: //www.cdc.gov/flu/professionals/treatment/0405antiviralguide.htm. Accessed 24 May 2005 . 4. Uyeki TM . Influenza diagnosis and treatment in children: a review of studies on clinically useful tests and antiviral treatment for influenza . Pediatr Infect Dis J 2003 ; 22 : 164 - 77 . 5. Bonner AB , Monroe KW , Talley LI , Klasner AE , Kimberlin DW . Impact complications and hospitalizations . Arch Intern Med 2003 ; 163 : 1667 - 72 . 10. Lee PY , Matchar DB , Clements DA , Huber J , Hamilton JD , Peterson ED. Economic analysis of influenza vaccination and antiviral treatment for healthy working adults . Ann Intern Med 2002 ; 137 : 225 - 31 . 11. Muennig PA , Khan K. Cost-effectiveness of vaccination versus treatment of influenza in healthy adolescents and adults . Clin Infect Dis 2001 ; 33 : 1879 - 85 . 12. Rothberg MB , Bellantonio S , Rose DN. Management of influenza in adults older than 65 years of age: cost-effectiveness of rapid testing and antiviral therapy . Ann Intern Med 2003 ; 139 : 321 - 9 .

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Michael B. Rothberg, Aleta B. Bonner, M. Hasan Rajab, Hyun Sun Kim, Barbara W. Stechenberg, David N. Rose. Effects of Local Variation, Specialty, and Beliefs on Antiviral Prescribing for Influenza, Clinical Infectious Diseases, 2006, 95-99, DOI: 10.1086/498517