- Email: [email protected]
National availability of influenza vaccine among medical subspecialty practices
Brief Reports
National Availability of Influenza Vaccine Among Medical Subspecialty Practices Matthew M. Davis, MD, MAPP, Pascale M. Wortley, MD, Serigne M. Ndiaye, PhD, Mark G. Woods, MS, Sarah J. Clark, MPH
Background: Influenza vaccination rates fall short of national goals, particularly among individuals whose chronic conditions predispose them to complications of influenza. Availability of influenza vaccine in medical subspecialists’ practices may affect vaccination rates among adults with chronic illness. Methods:
The practice sites of a national random sample of medical cardiology, endocrinology, and pulmonology physicians were contacted by telephone in February 2003 to March 2003 to determine which of them had influenza vaccine available to their patients during the 2002–2003 influenza season. The number of physicians in the practice and geographic location were also obtained.
Results:
Office staff at the practices of 1683 of 2013 eligible physicians were successfully contacted, and 1473 provided information about vaccine availability. Overall, 1094 (74%) of practices had influenza vaccine available during the 2002–2003 season. Availability differed significantly by subspecialty: 54% cardiology, 78% endocrinology, and 90% pulmonology (p⬍0.001). Influenza vaccine was more often available at subspecialists’ practices in the Northeast (80%) than in the South (74%), Midwest (71%), and West (70%; p⬍0.005). In multivariate analyses, pulmonology practices in all census regions and sizes were significantly more likely to have influenza vaccine available than was the reference cardiology practice. Several endocrinology practice types also had significantly higher influenza vaccine availability than those in cardiology practice, particularly in multi-physician practices.
Conclusions: Influenza vaccine availability varies widely across practices in the three medical subspecialties that provide care to the largest numbers of individuals with an indication for the vaccine in the United States. These findings have implications for the accessibility of influenza vaccine to individuals at high risk for morbidity and mortality associated with influenza. (Am J Prev Med 2004;26(4):307–310) © 2004 American Journal of Preventive Medicine
Introduction
V
accination against influenza is recommended for persons aged 50 years and older, adults with chronic disorders of the pulmonary or cardiovascular systems, and adults with chronic metabolic diseases, such as diabetes.1 Approximately 20 million Americans have pulmonary indications for influenza vaccination, 12 million have cardiac indications, and 7 million have diabetes indications.2
From the Division of General Internal Medicine (Davis) and Child Health Evaluation and Research (CHEAR) Unit, Division of General Pediatrics (Davis, Woods, Clark), University of Michigan, Ann Arbor, Michigan; and National Immunization Program, Centers for Disease Control and Prevention (Wortley, Ndiaye), Atlanta, Georgia Address correspondence and reprint requests to: Matthew M. Davis, MD, MAPP, University of Michigan, 300 NIB, 6C23, Ann Arbor MI 48109-0456. E-mail: [email protected].
However, measures of influenza vaccination coverage indicate that only about two in three persons aged 65 years and older and one in three persons aged 18 – 64 years with high-risk conditions receive the vaccine annually.1,3,4 These immunization rates are far below the national goals set in Healthy People 2010 5 of 90% for individuals aged 65 years and older and of 60% for other high-risk persons. Physicians’ recommendations for influenza vaccination are known to facilitate immunization efforts.6 Medical subspecialists recommend influenza vaccine to their patients less strongly than do their general internal medicine colleagues,7 but no prior studies have examined the availability of influenza vaccine at subspecialty practices. Lack of availability of influenza vaccine at the time of subspecialty visits may be a potentially modifiable obstacle to influenza vaccination of high-risk individuals.
Am J Prev Med 2004;26(4) © 2004 American Journal of Preventive Medicine • Published by Elsevier Inc.
0749-3797/04/$–see front matter doi:10.1016/j.amepre.2003.12.016
307
Methods Design A brief, cross-sectional telephone survey of staff members in medical subspecialty practices nationwide was conducted in February 2003 and March 2003 as part of an ongoing national study of subspecialty physicians approved by the Institutional Review Boards of the University of Michigan and the Centers for Disease Control and Prevention.
Sample The study sample was selected randomly from among physicians who self-reported internal medicine board certification and sub-board certification in cardiology, endocrinology, and pulmonology in the American Medical Association’s Physician Masterfile. The initial sample included 700 physicians from each subspecialty. Physicians were excluded who were in residency or in the military, had certification outside the three target subspecialties, were retired, were no longer in practice, or had moved out of the country.
Data Collection Interviewers contacted the practices of the sample physicians by telephone. Five attempts to contact each practice were made over a period of 2 weeks. Interviewers spoke to the practice staff member who answered the phone, confirmed that the physician in the sample practiced at that office, and asked the following: ●
●
Does this practice have influenza vaccine on hand currently, or has it had influenza vaccine on hand during this past “flu” season? (Yes/No/Don’t know) How many physicians practice at this office?
Data collection assumed the perspective of a patient: Staff responses were judged equivalent to the information that a patient would have received when calling to inquire about the availability of influenza vaccine. Responses of “don’t know” were considered non-informative to patients and were excluded from our analyses.
Data Analysis Chi-square analyses were used to assess the practice-reported availability of influenza vaccine, comparing groups by subspecialty, size of practice (one physician versus two or more physicians), and census region. Multivariate logistic regression was conducted to examine associations between the outcome and all independent variables. All possible interactions among the independent variables were investigated, and the only significant interaction (between size of practice and subspecialty) was included in the multivariate model. Analyses were conducted using Stata 7.0 (Stata Corp., College Station TX, 2001).
Results Sample Characteristics From the original sample of 2100 physicians, 87 were excluded for reasons stated in Methods. Practices for 308
1683 of the remaining 2013 physicians were successfully contacted by phone (84%), and staff at 1650 of these 1683 participated when contacted (98% response rate). Of the 1650 participants, 177 (11%) reported that they did not know about the availability of influenza vaccine at their practices. “Don’t know” responses were more likely from cardiology (13%) and endocrinology (11%) practices than from pulmonology practices (8%) (p⬍0.05) overall. Characteristics of the 1473 remaining subspecialty practices appear in Table 1.
Practice Factors Associated with Reported Availability of Influenza Vaccine Overall, 1094 practices (74%) reported having influenza vaccine available during the 2002–2003 influenza season. Availability differed significantly by subspecialty: Pulmonology practices were more likely than endocrinology practices, which were in turn more likely than cardiology practices, to report vaccine availability (Table 1). Size of practice and census region were also associated with vaccine availability. The associations of influenza vaccine availability with subspecialty and census region remained significant in a multivariate model (Table 2). All pulmonology practices grouped by size and region, as well as all multiphysician endocrinology practice groups, had significantly higher odds of reported vaccine availability than the reference cardiology group. In contrast, among cardiology groups alone, multi-physician practices in the Midwest, South, and West had significantly lower odds of vaccine availability than the Northeast reference group.
Discussion Influenza vaccination has been associated with reduced risk of hospitalization for cardiac and cerebrovascular disease,8,9 reduced risk of recurrent myocardial infarction,10 lower frequency of exacerbations of chronic obstructive pulmonary disease11 and asthma,12 and fewer hospitalizations for individuals with diabetes.13 Findings from this study suggest that persons with high-risk cardiac, pulmonary, and endocrine conditions have differential access to influenza vaccine based on their site of subspecialty care. Disparities across subspecialties may reflect different prioritization of immunization versus other visit objectives, or different proportions of patients with indications for influenza vaccine. These findings have implications for influenza vaccination among high-risk individuals. Although individuals motivated to obtain influenza vaccination have many options (e.g., physician office, workplace, pharmacy), data from the 1998 –1999 influenza season
American Journal of Preventive Medicine, Volume 26, Number 4
Table 1. Characteristics of medical subspecialty practices and proportion of practices reporting influenza vaccine availablility, 2002–2003 season Variable
Cardiology (%) nⴝ489
Endocrinology (%) nⴝ464
Characteristics of practicesa Size of practice* 1 physician 21 42 ⱖ2 physicians 79 58 Census region Northeast 28 29 Midwest 21 20 South 34 33 West 17 18 Proportion of practices reporting influenza vaccine availablility Size of practice** 1 physician 56 74 ⱖ2 physicians 54 80 Census region*** Northeast 66 85 Midwest 49 75 South 53 74 West 43 77 Total**** 54 78
Pulmonology (%) nⴝ520
Overall (%) nⴝ1473
31 69
31 69
29 14 37 20
29 18 35 18
85 92
74 74
90 96 91 85 90
80 71 74 70 74
*Proportions across subspecialties significantly different at p⬍0.001. **Proportion of practices with influenza vaccine available differed significantly between solo-physician and multi-physician practices within pulmonology at p⫽0.01. ***Proportion of practices with influenza vaccine available differed significantly among practices in different census regions within cardiology and overall at p⬍0.005. ****Comparison across all three subspecialties and all pairwise comparisons of subspecialties significant at p⬍0.001. a For characteristics of practices, column totals for each characteristic sum to 100%.
indicated that about half of influenza vaccine doses overall, and nearly two thirds of doses for individuals ⱖ65 years, were administered in physician offices.14 The relative proportions of vaccine administered in general medicine versus subspecialty settings, and the vaccination rates of high-risk individuals who see subspecialists versus those who do not, are not known. Nevertheless, the disparity in influenza vaccine availability among different subspecialty practices illuminates an opportunity to improve vaccination rates among high-risk persons, especially for individuals whose visit to a subspecialist during influenza season may be the most opportune time to be vaccinated.
Increasing Influenza Vaccine Availability at Subspecialty Practices A critical obstacle to improving vaccine availability is physicians’ prioritization of influenza vaccination during clinical encounters.7 One approach to address this obstacle is to implement provider education about the potential benefits of influenza vaccine in the context of subspecialty-specific information about other clinical objectives during outpatient visits. Another option is to establish standing orders for influenza vaccine in ambulatory care settings, which emphasize nurses’ contributions to the immunization effort and permit other-
Table 2. Odds of influenza vaccine availability reported in subspecialty practices Practice characteristics Cardiology 1 physician ⱖ2 physicians Endocrinology 1 physician ⱖ2 physicians Pulmonology 1 physician ⱖ2 physicians
Census regiona Northeast
Midwest
South
West
1.08 (.69–1.67) 1.00 (ref)
.68 (.37–1.24) .63 (.43–.92)
.67 (.38–1.18) .62 (.45–.87)
.52 (.29–.93) .48 (.33–.71)
2.51 (1.71–3.67) 3.60 (2.50–5.18)
1.57 (.92–2.70) 2.26 (1.33–3.84)
1.56 (.94–2.59) 2.24 (1.38–3.65)
1.21 (.71–2.06) 1.74 (1.04–2.91)
5.04 (3.11–8.16) 11.0 (7.07–17.2)
3.16 (1.68–5.94) 6.92 (3.85–12.5)
3.14 (1.75–5.60) 6.86 (3.99–11.8)
2.43 (1.33–4.43) 5.33 (3.03–9.36)
a Adjusted odds ratios (AOR) and 95% confidence intervals reflect results of multivariate logistic regression model of reported influenza vaccine availability on subspecialty, practice size, region, and an interaction term between practice size and subspecialty (n⫽1473). AOR are presented in reference to a cardiology practice in the Northeast region with ⱖ2 physicians.
Am J Prev Med 2004;26(4)
309
wise occupied physicians a more peripheral role in vaccine delivery.15 The latter approach would address concerns about low reimbursement for influenza vaccine administration among physicians who prioritize procedures and consultations. Other barriers to improving influenza vaccine availability may relate to region and practice size. Regional differences in reported availability may reflect physicians’ perception of the risk of influenza illness in their communities. Influenza activity in the United States does vary regionally, although not consistently from year to year.16 The association of practice size with vaccine availability is more complex, and may indicate differences in the procedure frequency across subspecialties that influence the clinical focus of typical outpatient visits. In general, the association of subspecialty practice characteristics with influenza vaccine availability merits further investigation, to understand better the roles of physician attitudes and specific practice factors, such as patient demographics and conditions, community setting, and frequency of office procedures that may either enhance or constrain the opportunity to administer vaccines in the subspecialty setting.
Limitations The principal limitation of this study is that practice staff members’ reports of influenza vaccine availability were not independently confirmed. The initial phase of work— distinct from a later physician survey—targeted practice staff who are the first point of contact and a common source of information for patients about the availability of clinical services. Of note, practice staff participated at an extremely high rate and were aware of vaccine availability in nearly 90% of cases. An additional caveat is that availability of influenza vaccine in physician practices is only one determinant of immunization among high-risk individuals. Efforts to improve influenza vaccination hinge on multiple physician and patient factors15 that were not addressed through the study methods.
Conclusions Differences across medical subspecialty practices regarding the availability of influenza vaccine may contribute to suboptimal influenza prevention among high-risk persons. Whereas community, workplace, or primary care immunization sites may be preferable for
310
some individuals, the lack of available vaccine at subspecialty practices represents a missed opportunity to reduce the burden of morbidity and mortality attributable to influenza. This work was funded by the Centers for Disease Control and Prevention through a cooperative Agreement with the Association of Teachers of Preventive Medicine.
References 1. Centers for Disease Control and Prevention. Prevention and control of influenza: recommendations of the Advisory Committee on Immunization Practices. MMWR Morb Mortal Wkly Rep 2003;52:1–36. 2. Singleton JA, Greby SM, Wooten KG, et al. Influenza, pneumococcal, and tetanus toxoid vaccination of adults—United States, 1993–1997. MMWR Morb Mortal Wkly Rep 2000;49:39 –52. 3. Centers for Disease Control and Prevention. Influenza and pneumococcal vaccination levels among persons aged ⱖ65 years. MMWR Morb Mortal Wkly Rep 2002;51:1019 –24. 4. Centers for Disease Control and Prevention. Preventive-care practices among persons with diabetes—United States, 1995 and 2001. MMWR Morb Mortal Wkly Rep 2002;51:965–9. 5. U.S. Department of Health and Human Services. Healthy people 2010 (conference ed., in 2 vols). Washington DC: U.S. Department of Health and Human Services, 2000. 6. Nichol KL, MacDonald R, Hauge M. Factors associated with influenza and pneumococcal vaccination behavior among high-risk adults. J Gen Intern Med 1996;11:673–7. 7. Nichol KL, Zimmerman RK. Generalist and subspecialist physicians’ knowledge, attitudes, and practices regarding influenza and pneumococcal vaccination for elderly and other high-risk patients. Arch Intern Med 2001;161:2702–8. 8. Nichol KL, Nordin J, Mullooly J, et al. Influence vaccination and reduction in hospitalizations for cardiac disease and stroke among the elderly. N Engl J Med 2003;348:1322–32. 9. Nichol KL, Wuorenma J, von Sternberg T. Benefits of influenza vaccination for low-, intermediate-, and high-risk senior citizens. Arch Intern Med 1998;158:1769 –76. 10. Naghavi M, Barlas Z, Siadaty S, et al. Association of influenza vaccination and reduced risk of recurrent myocardial infarction. Circulation 2000;102: 3039 –45. 11. Poole PJ, Chacko E, Wood-Baker RWB, et al. Influenza vaccine for patients with chronic obstructive pulmonary disease (Cochrane review). In: The Cochrane Library, 2003:issue 3. Oxford, England: Update Software. 12. Nathan RA, Geddes D, Woodhead M. Management of influenza in patients with asthma or chronic obstructive pulmonary disease. Ann Allergy Asthma Immunol 2001;87:447–54. 13. Colquhoun AJ, Nicholson KG, Botha JL, et al. Effectiveness of influenza vaccine in reducing hospital admissions in people with diabetes. Epidemiol Infect 1997;119:335–41. 14. Poel AJ, Singleton JA, Wooten K. Where adults reported receiving influenza vaccination, US, 1998/1999. In: Abstracts of the 35th National Immunization Conference. Atlanta GA: Centers for Disease Control and Prevention, 2001. 15. Briss PA, Rodewald LR, Hinman AR, et al. Reviews of evidence regarding interventions to improve vaccination coverage in children, adolescents, and adults. Am J Prev Med 2000;18(suppl 1):97–140. 16. Centers for Disease Control and Prevention. Update: influenza activity— United States and worldwide, 2002 to 2003 season, and composition of the 2003– 04 influenza vaccine. MMWR Morb Mortal Wkly Rep 2003;52:516 – 21.
American Journal of Preventive Medicine, Volume 26, Number 4
National Availability of Influenza Vaccine Among Medical Subspecialty Practices Matthew M. Davis, MD, MAPP, Pascale M. Wortley, MD, Serigne M. Ndiaye, PhD, Mark G. Woods, MS, Sarah J. Clark, MPH
Background: Influenza vaccination rates fall short of national goals, particularly among individuals whose chronic conditions predispose them to complications of influenza. Availability of influenza vaccine in medical subspecialists’ practices may affect vaccination rates among adults with chronic illness. Methods:
The practice sites of a national random sample of medical cardiology, endocrinology, and pulmonology physicians were contacted by telephone in February 2003 to March 2003 to determine which of them had influenza vaccine available to their patients during the 2002–2003 influenza season. The number of physicians in the practice and geographic location were also obtained.
Results:
Office staff at the practices of 1683 of 2013 eligible physicians were successfully contacted, and 1473 provided information about vaccine availability. Overall, 1094 (74%) of practices had influenza vaccine available during the 2002–2003 season. Availability differed significantly by subspecialty: 54% cardiology, 78% endocrinology, and 90% pulmonology (p⬍0.001). Influenza vaccine was more often available at subspecialists’ practices in the Northeast (80%) than in the South (74%), Midwest (71%), and West (70%; p⬍0.005). In multivariate analyses, pulmonology practices in all census regions and sizes were significantly more likely to have influenza vaccine available than was the reference cardiology practice. Several endocrinology practice types also had significantly higher influenza vaccine availability than those in cardiology practice, particularly in multi-physician practices.
Conclusions: Influenza vaccine availability varies widely across practices in the three medical subspecialties that provide care to the largest numbers of individuals with an indication for the vaccine in the United States. These findings have implications for the accessibility of influenza vaccine to individuals at high risk for morbidity and mortality associated with influenza. (Am J Prev Med 2004;26(4):307–310) © 2004 American Journal of Preventive Medicine
Introduction
V
accination against influenza is recommended for persons aged 50 years and older, adults with chronic disorders of the pulmonary or cardiovascular systems, and adults with chronic metabolic diseases, such as diabetes.1 Approximately 20 million Americans have pulmonary indications for influenza vaccination, 12 million have cardiac indications, and 7 million have diabetes indications.2
From the Division of General Internal Medicine (Davis) and Child Health Evaluation and Research (CHEAR) Unit, Division of General Pediatrics (Davis, Woods, Clark), University of Michigan, Ann Arbor, Michigan; and National Immunization Program, Centers for Disease Control and Prevention (Wortley, Ndiaye), Atlanta, Georgia Address correspondence and reprint requests to: Matthew M. Davis, MD, MAPP, University of Michigan, 300 NIB, 6C23, Ann Arbor MI 48109-0456. E-mail: [email protected].
However, measures of influenza vaccination coverage indicate that only about two in three persons aged 65 years and older and one in three persons aged 18 – 64 years with high-risk conditions receive the vaccine annually.1,3,4 These immunization rates are far below the national goals set in Healthy People 2010 5 of 90% for individuals aged 65 years and older and of 60% for other high-risk persons. Physicians’ recommendations for influenza vaccination are known to facilitate immunization efforts.6 Medical subspecialists recommend influenza vaccine to their patients less strongly than do their general internal medicine colleagues,7 but no prior studies have examined the availability of influenza vaccine at subspecialty practices. Lack of availability of influenza vaccine at the time of subspecialty visits may be a potentially modifiable obstacle to influenza vaccination of high-risk individuals.
Am J Prev Med 2004;26(4) © 2004 American Journal of Preventive Medicine • Published by Elsevier Inc.
0749-3797/04/$–see front matter doi:10.1016/j.amepre.2003.12.016
307
Methods Design A brief, cross-sectional telephone survey of staff members in medical subspecialty practices nationwide was conducted in February 2003 and March 2003 as part of an ongoing national study of subspecialty physicians approved by the Institutional Review Boards of the University of Michigan and the Centers for Disease Control and Prevention.
Sample The study sample was selected randomly from among physicians who self-reported internal medicine board certification and sub-board certification in cardiology, endocrinology, and pulmonology in the American Medical Association’s Physician Masterfile. The initial sample included 700 physicians from each subspecialty. Physicians were excluded who were in residency or in the military, had certification outside the three target subspecialties, were retired, were no longer in practice, or had moved out of the country.
Data Collection Interviewers contacted the practices of the sample physicians by telephone. Five attempts to contact each practice were made over a period of 2 weeks. Interviewers spoke to the practice staff member who answered the phone, confirmed that the physician in the sample practiced at that office, and asked the following: ●
●
Does this practice have influenza vaccine on hand currently, or has it had influenza vaccine on hand during this past “flu” season? (Yes/No/Don’t know) How many physicians practice at this office?
Data collection assumed the perspective of a patient: Staff responses were judged equivalent to the information that a patient would have received when calling to inquire about the availability of influenza vaccine. Responses of “don’t know” were considered non-informative to patients and were excluded from our analyses.
Data Analysis Chi-square analyses were used to assess the practice-reported availability of influenza vaccine, comparing groups by subspecialty, size of practice (one physician versus two or more physicians), and census region. Multivariate logistic regression was conducted to examine associations between the outcome and all independent variables. All possible interactions among the independent variables were investigated, and the only significant interaction (between size of practice and subspecialty) was included in the multivariate model. Analyses were conducted using Stata 7.0 (Stata Corp., College Station TX, 2001).
Results Sample Characteristics From the original sample of 2100 physicians, 87 were excluded for reasons stated in Methods. Practices for 308
1683 of the remaining 2013 physicians were successfully contacted by phone (84%), and staff at 1650 of these 1683 participated when contacted (98% response rate). Of the 1650 participants, 177 (11%) reported that they did not know about the availability of influenza vaccine at their practices. “Don’t know” responses were more likely from cardiology (13%) and endocrinology (11%) practices than from pulmonology practices (8%) (p⬍0.05) overall. Characteristics of the 1473 remaining subspecialty practices appear in Table 1.
Practice Factors Associated with Reported Availability of Influenza Vaccine Overall, 1094 practices (74%) reported having influenza vaccine available during the 2002–2003 influenza season. Availability differed significantly by subspecialty: Pulmonology practices were more likely than endocrinology practices, which were in turn more likely than cardiology practices, to report vaccine availability (Table 1). Size of practice and census region were also associated with vaccine availability. The associations of influenza vaccine availability with subspecialty and census region remained significant in a multivariate model (Table 2). All pulmonology practices grouped by size and region, as well as all multiphysician endocrinology practice groups, had significantly higher odds of reported vaccine availability than the reference cardiology group. In contrast, among cardiology groups alone, multi-physician practices in the Midwest, South, and West had significantly lower odds of vaccine availability than the Northeast reference group.
Discussion Influenza vaccination has been associated with reduced risk of hospitalization for cardiac and cerebrovascular disease,8,9 reduced risk of recurrent myocardial infarction,10 lower frequency of exacerbations of chronic obstructive pulmonary disease11 and asthma,12 and fewer hospitalizations for individuals with diabetes.13 Findings from this study suggest that persons with high-risk cardiac, pulmonary, and endocrine conditions have differential access to influenza vaccine based on their site of subspecialty care. Disparities across subspecialties may reflect different prioritization of immunization versus other visit objectives, or different proportions of patients with indications for influenza vaccine. These findings have implications for influenza vaccination among high-risk individuals. Although individuals motivated to obtain influenza vaccination have many options (e.g., physician office, workplace, pharmacy), data from the 1998 –1999 influenza season
American Journal of Preventive Medicine, Volume 26, Number 4
Table 1. Characteristics of medical subspecialty practices and proportion of practices reporting influenza vaccine availablility, 2002–2003 season Variable
Cardiology (%) nⴝ489
Endocrinology (%) nⴝ464
Characteristics of practicesa Size of practice* 1 physician 21 42 ⱖ2 physicians 79 58 Census region Northeast 28 29 Midwest 21 20 South 34 33 West 17 18 Proportion of practices reporting influenza vaccine availablility Size of practice** 1 physician 56 74 ⱖ2 physicians 54 80 Census region*** Northeast 66 85 Midwest 49 75 South 53 74 West 43 77 Total**** 54 78
Pulmonology (%) nⴝ520
Overall (%) nⴝ1473
31 69
31 69
29 14 37 20
29 18 35 18
85 92
74 74
90 96 91 85 90
80 71 74 70 74
*Proportions across subspecialties significantly different at p⬍0.001. **Proportion of practices with influenza vaccine available differed significantly between solo-physician and multi-physician practices within pulmonology at p⫽0.01. ***Proportion of practices with influenza vaccine available differed significantly among practices in different census regions within cardiology and overall at p⬍0.005. ****Comparison across all three subspecialties and all pairwise comparisons of subspecialties significant at p⬍0.001. a For characteristics of practices, column totals for each characteristic sum to 100%.
indicated that about half of influenza vaccine doses overall, and nearly two thirds of doses for individuals ⱖ65 years, were administered in physician offices.14 The relative proportions of vaccine administered in general medicine versus subspecialty settings, and the vaccination rates of high-risk individuals who see subspecialists versus those who do not, are not known. Nevertheless, the disparity in influenza vaccine availability among different subspecialty practices illuminates an opportunity to improve vaccination rates among high-risk persons, especially for individuals whose visit to a subspecialist during influenza season may be the most opportune time to be vaccinated.
Increasing Influenza Vaccine Availability at Subspecialty Practices A critical obstacle to improving vaccine availability is physicians’ prioritization of influenza vaccination during clinical encounters.7 One approach to address this obstacle is to implement provider education about the potential benefits of influenza vaccine in the context of subspecialty-specific information about other clinical objectives during outpatient visits. Another option is to establish standing orders for influenza vaccine in ambulatory care settings, which emphasize nurses’ contributions to the immunization effort and permit other-
Table 2. Odds of influenza vaccine availability reported in subspecialty practices Practice characteristics Cardiology 1 physician ⱖ2 physicians Endocrinology 1 physician ⱖ2 physicians Pulmonology 1 physician ⱖ2 physicians
Census regiona Northeast
Midwest
South
West
1.08 (.69–1.67) 1.00 (ref)
.68 (.37–1.24) .63 (.43–.92)
.67 (.38–1.18) .62 (.45–.87)
.52 (.29–.93) .48 (.33–.71)
2.51 (1.71–3.67) 3.60 (2.50–5.18)
1.57 (.92–2.70) 2.26 (1.33–3.84)
1.56 (.94–2.59) 2.24 (1.38–3.65)
1.21 (.71–2.06) 1.74 (1.04–2.91)
5.04 (3.11–8.16) 11.0 (7.07–17.2)
3.16 (1.68–5.94) 6.92 (3.85–12.5)
3.14 (1.75–5.60) 6.86 (3.99–11.8)
2.43 (1.33–4.43) 5.33 (3.03–9.36)
a Adjusted odds ratios (AOR) and 95% confidence intervals reflect results of multivariate logistic regression model of reported influenza vaccine availability on subspecialty, practice size, region, and an interaction term between practice size and subspecialty (n⫽1473). AOR are presented in reference to a cardiology practice in the Northeast region with ⱖ2 physicians.
Am J Prev Med 2004;26(4)
309
wise occupied physicians a more peripheral role in vaccine delivery.15 The latter approach would address concerns about low reimbursement for influenza vaccine administration among physicians who prioritize procedures and consultations. Other barriers to improving influenza vaccine availability may relate to region and practice size. Regional differences in reported availability may reflect physicians’ perception of the risk of influenza illness in their communities. Influenza activity in the United States does vary regionally, although not consistently from year to year.16 The association of practice size with vaccine availability is more complex, and may indicate differences in the procedure frequency across subspecialties that influence the clinical focus of typical outpatient visits. In general, the association of subspecialty practice characteristics with influenza vaccine availability merits further investigation, to understand better the roles of physician attitudes and specific practice factors, such as patient demographics and conditions, community setting, and frequency of office procedures that may either enhance or constrain the opportunity to administer vaccines in the subspecialty setting.
Limitations The principal limitation of this study is that practice staff members’ reports of influenza vaccine availability were not independently confirmed. The initial phase of work— distinct from a later physician survey—targeted practice staff who are the first point of contact and a common source of information for patients about the availability of clinical services. Of note, practice staff participated at an extremely high rate and were aware of vaccine availability in nearly 90% of cases. An additional caveat is that availability of influenza vaccine in physician practices is only one determinant of immunization among high-risk individuals. Efforts to improve influenza vaccination hinge on multiple physician and patient factors15 that were not addressed through the study methods.
Conclusions Differences across medical subspecialty practices regarding the availability of influenza vaccine may contribute to suboptimal influenza prevention among high-risk persons. Whereas community, workplace, or primary care immunization sites may be preferable for
310
some individuals, the lack of available vaccine at subspecialty practices represents a missed opportunity to reduce the burden of morbidity and mortality attributable to influenza. This work was funded by the Centers for Disease Control and Prevention through a cooperative Agreement with the Association of Teachers of Preventive Medicine.
References 1. Centers for Disease Control and Prevention. Prevention and control of influenza: recommendations of the Advisory Committee on Immunization Practices. MMWR Morb Mortal Wkly Rep 2003;52:1–36. 2. Singleton JA, Greby SM, Wooten KG, et al. Influenza, pneumococcal, and tetanus toxoid vaccination of adults—United States, 1993–1997. MMWR Morb Mortal Wkly Rep 2000;49:39 –52. 3. Centers for Disease Control and Prevention. Influenza and pneumococcal vaccination levels among persons aged ⱖ65 years. MMWR Morb Mortal Wkly Rep 2002;51:1019 –24. 4. Centers for Disease Control and Prevention. Preventive-care practices among persons with diabetes—United States, 1995 and 2001. MMWR Morb Mortal Wkly Rep 2002;51:965–9. 5. U.S. Department of Health and Human Services. Healthy people 2010 (conference ed., in 2 vols). Washington DC: U.S. Department of Health and Human Services, 2000. 6. Nichol KL, MacDonald R, Hauge M. Factors associated with influenza and pneumococcal vaccination behavior among high-risk adults. J Gen Intern Med 1996;11:673–7. 7. Nichol KL, Zimmerman RK. Generalist and subspecialist physicians’ knowledge, attitudes, and practices regarding influenza and pneumococcal vaccination for elderly and other high-risk patients. Arch Intern Med 2001;161:2702–8. 8. Nichol KL, Nordin J, Mullooly J, et al. Influence vaccination and reduction in hospitalizations for cardiac disease and stroke among the elderly. N Engl J Med 2003;348:1322–32. 9. Nichol KL, Wuorenma J, von Sternberg T. Benefits of influenza vaccination for low-, intermediate-, and high-risk senior citizens. Arch Intern Med 1998;158:1769 –76. 10. Naghavi M, Barlas Z, Siadaty S, et al. Association of influenza vaccination and reduced risk of recurrent myocardial infarction. Circulation 2000;102: 3039 –45. 11. Poole PJ, Chacko E, Wood-Baker RWB, et al. Influenza vaccine for patients with chronic obstructive pulmonary disease (Cochrane review). In: The Cochrane Library, 2003:issue 3. Oxford, England: Update Software. 12. Nathan RA, Geddes D, Woodhead M. Management of influenza in patients with asthma or chronic obstructive pulmonary disease. Ann Allergy Asthma Immunol 2001;87:447–54. 13. Colquhoun AJ, Nicholson KG, Botha JL, et al. Effectiveness of influenza vaccine in reducing hospital admissions in people with diabetes. Epidemiol Infect 1997;119:335–41. 14. Poel AJ, Singleton JA, Wooten K. Where adults reported receiving influenza vaccination, US, 1998/1999. In: Abstracts of the 35th National Immunization Conference. Atlanta GA: Centers for Disease Control and Prevention, 2001. 15. Briss PA, Rodewald LR, Hinman AR, et al. Reviews of evidence regarding interventions to improve vaccination coverage in children, adolescents, and adults. Am J Prev Med 2000;18(suppl 1):97–140. 16. Centers for Disease Control and Prevention. Update: influenza activity— United States and worldwide, 2002 to 2003 season, and composition of the 2003– 04 influenza vaccine. MMWR Morb Mortal Wkly Rep 2003;52:516 – 21.
American Journal of Preventive Medicine, Volume 26, Number 4