1. Influenza Vaccination Among Asthmatic Patients During the “Flu” Season
Jalal Zuberi, Nabila Haque, Mary Hixson,
Sonja Hutchins
Immunization

2. Background Asthma a substantial health problem 15 million Americans
5 million <18 years
Advisory groups recommend influenza
vaccine for asthmatic patients
High national health objectives for 2010
(60%-90%)
Asthma is a substantial health burden in the US:
15 million persons with asthma in US
5 million <18 years. The prevalence among children is increasing.
Several advisory groups recommend influenza vaccination (AAP, ACIP, and the Expert Panel for the Diagnosis and Management of Asthma)
Our national health objectives to achieve by 2010 call for high vaccine coverage, ranging from 60% to 90% depending on age (60%: yrs and 90% >65 yrs)
Vaccination coverage among high risk populations has been found to be suboptimal I wanted to know whether we experienced the same problem in a faculty academic practice at Morehouse School of Medicine, and if so, what might be the reasons for low coverage.
Coverage in an academic practice in theory should be high because of its commitment to teach/train medical students and residents. If coverage is not high here, where would it be high?

3. Influenza Vaccine Coverage in Asthmatic Patients
Author(Year)
Study Design
Population
Coverage
Kramarz
( )
Cohort
68,839 <18 yrs
9%-10%
Chung
(1998)
Cross-sectional
mos
25%
Rangel
2,000+
18-64 yrs
>=65yrs
32%
63%
The recent studies of vaccination coverage among asthmatic patients found coverage among children to be 9%-25%, while coverage among adults was higher, from 32%-63% with elderly persons 65 years or older having the highest coverage.
These studies examined vaccine coverage during the latter 1990s before the national vaccine shortages.
Two studies had very large study populations: a retrospective cohort study by Kramar examined 69,000 children <18 years in 4 large HMOS on the west coast and Maria Rangel examined thousands of high risk adults from the National Health Interview Survey.
For example,
Recent studies that examined coverage among asthmatic children and adults found very low levels of vaccination
Kramar, in flu season, examined the vaccination coverage of a large population of asthmatic children <18 years of age in managed care organization and found only 9-10% to be vaccinated .
In 1998, Chung in a cross-sectional study found 25% of young children 6-48 months to be vaccinated
Maria Rangel found using data from the National health Interview Survey , a crossectional survey of the noninstitutionalized US population in 1998, that 32% of high-risk adults years of age were vaccinated and 63% of elderly 65 and older were vaccinated.

4. Influenza Vaccine Safety in Asthmatic Patients
Author(Year)
Study Design
Population
Difference
ALA (2000)
RCT
yrs
1.1 NS
Kramarz
( )
Cohort
70,753 <18 yrs
Cates
(<2000)
5 RT
Variable
Nicholson
(1998)
yrs NS
Although the vaccine is highly efficacious ( XX%-XX%), one reason for suboptimal coverage may be due to the concern that the vaccine causes an exacerbation of asthma.
In general, recent studies that examined asthma exacerbation after inactivated trivalent vaccination found no increased risk of exacerbations after influenza vaccination.
For example,
The American Lung Multicenter randomized control trial recently published in the NEJM found that in 2000 children 1-6 years of age there was not a significant difference in the number of exacerbations as defined as ……
Kramar in an observational, large retrospective cohort study of 70,000 children <18 years of age in managed care organizations over 3 influenza season found a lower number of exacerbations
Cates reviewed the literature and found 5 randomized trials that showed variable results but the sample sizes where small.
Nicholson in 1998 found a higher number of exacerbations but when the patients years of age with a respiratory illness not due to influenza were excluded them the number of exacerbations was not significant.
+ IRR

5. Objectives
Assess influenza vaccine coverage among asthmatic patients in an academic medical practice
Identify factors that predict influenza vaccination
Now that there is evidence that the vaccine is safe and effective in asthmatic patients, we undertook a study to:
Assess influenza vaccine coverage in an………….
Identify factors the predict vaccination.
Dr. Hutchins will describe our study methods and results.

6. Methods—Study Design Retrospective cohort study
influenza season
Medical record review,
Information from record:
Date of birth Insurance
Gender Asthma severity
Race/ethnicity Influenza vaccine
When Dr. Zuberi contacted me to provide technical assistance to the study, I leaped at the opportunity to help with documenting vaccination coverage of a population at high risk for influenza and its complications for several reasons (asthma, African Americans). If coverage is low, information on the predictors could help identifying interventions for improving vaccination coverage.
The study conducted was a retrospective cohort design of vaccination coverage of asthmatic patients during the influenza season, before the national vaccine shortages. The season was defined as September 1, 1997-April 30, 1998.
The medical records of asthmatic patients in the academic medical practice were examined in
Information abstracted from the medical record included:
…………history of influenza vaccination only a date of influenza vaccination was considered evidence of vaccination. Children with at least a dose of vaccine were considered vaccinated.

7. Methods-Study Population
Computerized billing list of patients with ICD- 9 code 493 for asthma
Visit between September 1, 1997
April 30, 1998
No other chronic diseases
No allergic reactions to vaccination
To identify children with asthma :
All patients from a computerized billing list of patients with the International Classification of Diseases, Ninth Revision (ICD-9) code for asthma were selected.
These patients had to have visited the academic medical practice during the flu season between September 1, April 30, 1998.
Did not have other chronic diseases (COPD or bronchopulmonary dysplasia, sickle cell , and immunosuppressive conditions) that could exacerbate asthma.
No allergic contraindications to vaccination (anaphylactic hypersensitivity to egg protein a previous history of allergic reaction to influenza vaccination.

8. Methods—Asthma Severity
Symptoms Nocturnal PEF
Mild >1/week, >2/month >80%
<1/day
Moderate Daily >1/week %-80%
Severe Continual Frequent <60%
The clinical illness of asthma followed the definitions of the Global Strategy for Asthma Management and Prevention Workshop sponsored by the National Heart, Lung and Blood Institute of the NIH in 1998.
Mild defined as infrequent symptoms: >1 week but <1 per day and nighttime symptoms of >2 month and peak expiratory flow of >80%. Moderate was defined a daily symptom, nighttime symptoms >1 per week and PEF between 60% and 80%. Severe was defined as continual symptoms and frequent nighttime symptoms and PEF <60%.

9. Study Population-Age Distribution N=216
Age (Years)
Number
Percent
<5 37 17
5-17 71 33
18-64 93 43
>65 14 7
The next series of slides describes the study population asthmatic patients seen during the influenza season were included. One half were children and one half were adults.

10. Study Population– Gender and and Race/Ethnicity
Number
Percent(%)
Female
126 59
Male 88 41
Race/Ethnicity
African American 78 96
White American 2 4
Most were female and African American.

11. Study Population--Insurance Status
Number
Percent
Private
124 57
Public 81 38
Other(Military) 1
0.5
None 10 5
Nearly all had health insurance (95%) only 5% did not. Of those with an health insurance, most had a private insurance.

12. Study Population—Asthma Severity
Age (Years)
Number
Percent
Mild 54 26
Mild-Moderate 20 10
Moderate 32 16
Moderate-Severe 24 12
Severe 22 11
Unclassified
The clinical illness of asthma was classified for 2/3rds of the patients. Of those one half had illness from mild to between mild and moderate and the other one half had moderate to severe illness.

13. Influenza Vaccine Coverage of Asthma Patients in and National Health Objectives (N=216)
90%
60%
Vaccination coverage for this population, overall, was 31%. 66 of the 216 patients had received an influenza vaccine during the season.
In contrast, the health people 2010 objectives call for 60% of high risk adults years of age to be vaccinated and 90% of the elderly 65 years of age or older.
31%

14. Influenza Vaccine Coverage in Asthma Patients By Age Group, 1997-1998
National Health Objective (>=65yrs), 2000
We found influenza vaccine coverage to increase with age. It was only 5% for children younger than five, 17% for school-aged children 5-17 years, 47% for adults years of age and 57% for elderly 65 years of age or older, very close to the National Health objective for of 60% in this population

15. Predictors of Influenza Vaccination
We examined a number potential predictors of influenza vaccination.

16. Predictor of Influenza Vaccination in Asthma Patients-Age
Total
%Vaccinated
RR (95%CI)
<17 yrs
108 12
Reference
>18 yrs
107 49
4.0( )
Vaccine coverage for female was 50% higher than the coverage for males, but not statistically significant.

17. Predictor of Influenza Vaccination in Asthma Patients-Gender
Total
%Vaccinated
RR (95%CI)
Female
126 36
1.5( )
Male 88 24
Reference
Vaccine coverage for female was 50% higher than the coverage for males, but not statistically significant.

18. Predictor of Influenza Vaccination in Asthma Patients-Race/Ethnicity
Total
%Vaccinated
RR (95%CI)
African American 78 32
Reference
White American 2
100
3.1( )+
Very small number of white patients examined. Of those, all were vaccinated compared with only 32% of African Americans. Thus, white were 3-fold higher vaccine coverage than African Americans but this was not significant at the P value <0.05 , although it was closely.
+Fisher’s Exact, P=0.11

19. Predictor of Influenza Vaccination in Asthma Patients-Insurance Status
Total
%Vaccinated
RR(95%CI)
Private
124 23
Undefined*
Public 81 46
Undefined+
None/Other 11
Reference
None of the 11 asthma patients with no health insurance were vaccinated compared with 23% with private insurance and public insurance. Because the number of the zero, Risk ratios could not be computed. The higher vaccination coverage for those insured was statistically significant for those with public insurance and close for those with private insurance
Fisher’s Exact: +P <0.01 and * P=0.12

20. Predictor of Influenza Vaccination in Asthma Patients--Severity of Asthma
13.1*
5.6*
4.5*
As severity of asthma increased so did the percentage of asthma patients vaccinated against influenza, from 5-6% for those with mild or between mild and moderate asthma, one third for moderate or between moderate and severe asthma, and 73% for those with severe.
For those with moderate to severe asthma vaccine coverage was 6 to 13 fold higher than for mild illness. These were statistically significant.
1.0
0.9
Number=RR
* P<0.05

21. Preliminary Results Follow-Up Study 2000-2001 Influenza Season
Currently, a follow-up study is underway to examine vaccine coverage during the Influenza Season. This study was undertaken to:
Ascertain vaccination history and predictors of vaccination more completely by interviewing the patients in addition to the medical record review. Similar studies are to be conducted in other provider settings and compared to the academic practice (Specialty Practice and County Hospital Outpatient Department).
It too was a retrospective cohort study in which records were reviewed in

22. Influenza Vaccine Coverage in Asthma Patients By Season
National Vaccine Shortage
66/216
To date, of the 240 patients with asthma eligible for this study, the record review and telephone interview is complete for 121.
Of the 121, only 6 were vaccinated (5%). This is a 84% reduction in vaccine coverage from the season. Coverage during the season was measured during the first year of a vaccine shortage.
Total: 212
95 complete
ever 24/142 children
ever 14/70 adult
Flu record 3/142 children
flu 6/70 adults
Underway
To assess more completeness of vaccination status
More detailed info or vaccination status and reasons for lack of vaccination.
6/121

23. Patient Reported Reasons For Lack of Vaccination (N=113)
Number
Percent
Doctor did not advise 73 65
Safety concern 21 16
Vaccine not effective 5 4
Not convenient
Did not get around to it
No need for vaccine 2
Sick at visit
Afraid of needles 1
Did not know
Information on why asthma patients were not vaccinated was available for 113 of the 121 patients. Of these, the most frequent reason was that the doctor did not recommend that they be vaccinated. One of the six patients were concerned about the safety and influenza vaccination would make them sick. Less frequent reasons included vaccine not effective, not convenient to get vaccinated , not a priority—did not get around to it, no need for the vaccine, sick at the time of visit, afraid of needles and did not know.

24. Conclusions Suboptimal influenza vaccine coverage
Coverage improved with age and severity
of asthma
Predictors of vaccination:
Adults
Female
Insurance
Moderate/severe asthma
In this population of asthmatic patients in which one half have moderate to severe asthma, mostly female, mostly African American, nearly all insured had a suboptimal vaccination coverage
Although coverage was suboptimal, it was higher than found in other studies.
Coverage improved with age and severity of asthma. Reaching nearly 60% for the elderly aged 65 or older and over 70% for those with severe asthma.
Predictors of vaccination included being an adult 18 years of age or older or a female, having insurance (particularly public), and moderate to severe asthma.

25. Conclusion (Continued)
Substantial drop in vaccine coverage during national vaccine shortage
No doctor advice--most frequent reason for
lack of vaccination
Comprehensive follow-up study underway to:
Compare various providers (specialty and county hospital outpatient department)
Use findings as baseline for intervention study
There was a substantial drop in influenza vaccination during the vaccine shortage.
The most common reason was lack of doctors advice for vaccination.
The comprehensive follow up study should help document more completely current flu vaccine coverage in the academic practice, allow us to compare coverage and predictors in other provider settings and use our findings as a baseline for intervention studies in these practices.