Reduction in Mortality Associated with
Influenza and Pneumococcal
Vaccination of Nursing Home Residents
Sophia Kazakova1, Dale Bratzler2, Wato Nsa2, Amy
Curtis1 Linda McKibben1, Abigail Shefer1, Lynn Steele1,
Chesley Richards1, John Jernigan1
Centers for Disease Control and Prevention1
Oklahoma Foundation of Medical Quality2
Background
• In the US 1.6 million residents live in more
than 17,000 long term care facilities (LTCF)
• Incidence of invasive pneumococcal
disease 4 times higher among LTCF
residents compared to older adults in the
community1
• 90% of influenza related deaths in the US
occur among the elderly2
1Kupronis
et.al. J Am Geriatr Soc 2003;51:1520-1525.
2Thompson
et. Al. JAMA 2003;289:179
Documented Influenza and Pneumococcal Vaccination
Among US Nursing Home Residents, 1995-1999
100
Healthy People 2010 Goal
% Vaccinated
80
63
64
66
60
38
40
24
28
20
0
Influenza
Pneumococcal
Buikema AR, Singleton JA, et al. [abstract] Centers for Disease
Control and Prevention, 35th National Immunization Conference.
1995
1997
1999
Vaccine Efficacy Among Elderly
• General and LTCF elderly populations
– Influenza1
• Reduces respiratory illness, pneumonia and
death
– Pneumococcal vaccine2
• Small sample size
• unable to examine facility-level
characteristics
1Gross
PA, et al. Ann Int Med 1995;123:518-527
2 Jackson
LA, et al. N Engl J Med 2003;348:1747-55, 2003
Study Objective
• To examine the impact of individual
influenza and pneumococcal
vaccination of Nursing Home
residents on individual mortality
controlling for individual and
facility-level characteristics
The Immunization Standing Orders Project
Centers for Disease Control and Prevention and
Center for Medicare and Medicaid Services
14 States
DC
Methods
Study Population
– 20 LTCF within each state
• Size, influenza program type, and QIO participation
– 100 residents randomly sampled from each facility
• November 2000 – January 2001
• November 2001 – January 2002
Data Sources
– Medical record review
• Influenza (October – December of the study year)
• Pneumococcal vaccination status (life-time history)
– Minimum Data Set (MDS)
• Coexisting conditions, Activities of Daily Living
– Medicare Claims and Enrollment Database
• Vital status and demographics
Methods (continued)
• Outcome
– Individual Vital Status (dead/alive) 14 days or
more after flu vaccination during influenza
season (November – April)
• Predictor Variables
– Individual influenza and pneumococcal
vaccination
• Control Variables
– Age, sex, race/ethnicity, diabetes, COPD, stroke,
cancer, renal failure, atherosclerotic heart
disease and CHF, dementia, ADL
Methods (continued)
• Multilevel multivariate statistical
analysis
– Two-level random intercept logistic
regression modeling with logit link
function
– HLM 5; Hierarchical Linear Modeling;
Scientific Software International, Inc.
Lincolnwood, IL
Study Cohorts
2000-2001
(Cohort One)
2001-2002
(Cohort Two)
22,317
21,773
277
260
Coverage Survey or MDS data
not available
2,904 (13%)
2,907 (13%)
Terminal illness, under Hospice
Care, or HIV/AIDS
542 (2.4%)
521 (2.4%)
5,130 (22.9%)
3,411 (15.7%)
13,267 (59.4%)
13,891 (63.8%)
273
259
Original random sample
Nursing Homes
Exclusions:
Vaccination Status Unknown
Final Cohort Size
Number of Nursing Homes
Results
Results: Vaccination Rates
Received
Influenza
Vaccine
Received
Pneumococcal
Vaccine
2000-2001
Cohort One
(N=13,267)
2001-2002
Cohort One
(N=13,891)
61%
61%
39%
44%
% Vaccinated
Vaccination Status
45
40
35
30
25
20
15
10
5
0
Cohort One
Cohort Two
Both
Flu
Pne
Demographic Characteristics
Cohort 2000-2001
Both
Vaccines
N = 6,130
Flu
Only
N = 5,160
Pneumo
Only
N = 1,007
Neither
N = 1,063
Male, %
27.7
29.3
28.9
29.4
White, %
79.7
80.3
81.5
83.4
Under 65 years
6.0
5.6
6.8
5.9
65 to 74
11.9
12.6
14.1
16.9
75 to 84
34.8
34.6
36.8
36.3
85 years or older
47.3
47.3
43.3
40.8
Age Groups, %
Co-Existing Conditions (%)
Cohort 2000-2001
Both
Vaccines
Flu
Only
Pneumo
Only
Neither
Heart disease
29.7
30.8
33.4
30.9
COPD
16.6
16.7
16.4
20.8
Diabetes
23.2
23.7
26.0
24.2
Renal failure
4.4
5.1
5.3
6.7
Dementia
53.6
54.2
45.8
35.0
Cancer
6.7
6.3
6.9
11.7
Stroke
24.5
23.6
22.6
18.3
Mean ADL
11. 6
10.9
10.8
10.4
Association Between Vaccination and AllCause Mortality, 2000-2002
% Dead
Cohort One
Cohort Two
Both Vaccines
11.7
12.4
Influenza Only
14.1
15.2
Pneumo
Only
15.4
17.02
None
19.5
21.1
Vaccination
Association Between Vaccination
and All-Cause Mortality, 2000-2002
Adjusted* RR (CI)
Cohort One
Cohort Two
Received Both Vaccines
0.55 (0.49 – 0.69)
0.58 (0.521 – 0.67)
Received Influenza Only
0.75 (0.62 – 0.86)
0.73 (0.648 – 0.87)
Received Pneumo. Only
0.81 (0.65 – 0.98)
0.80 (0.676 – 0.9)
Received None (Ref)
*Control Variables: diabetes, stroke, cancer, renal failure,
heart disease, dementia, ADL score, sex, age
Facility-Level Vaccination Coverage
• In initial analysis, without exclusion of
residents with unknown vaccination
status
– >80% coverage with influenza
significantly and independently
associated with decreased risk of
mortality
• After exclusion, this association
became insignificant
Summary
• The first prospective study of Nursing
Home residents to demonstrate a
significant protective effect of
pneumococcal vaccination on mortality.
• Confirmed the important role of
influenza vaccination in preventing the
adverse outcome.
Limitations
•
•
•
•
Facility selection non-randomized
Vaccination status non-randomized
Possibility of exclusion bias
Possibility of misclassification bias in
ascertaining vaccination status
• Possibility of unmeasured confounders
Health Policy Implications
• Unvaccinated residents are at increased risk for
adverse outcomes
• Failure to vaccinate residents of long term care
facilities is a patient safety issue
• Wider implementation of standing orders programs or
other effective interventions to increase vaccination
rates
• A better understanding of the barriers to vaccination
in this setting is needed
• Poor documentation of vaccination status in NHs
Acknowledgments
• CDC
– Jeremy Miller
• Oklahoma Foundation
For Medical Quality
– Jennifer O’Hagan
• CMS
– Jackie Harley
– Kathy Pirotte
– Peter Houck
Nursing Home Characteristics (n=249)
Category
Skilled Nursing Facility/
Nursing Facility (dual certification)
52%
Skilled Nursing Facility/
Nursing Facility (distinct part certified)
39%
Skilled nursing facility
4%
Nursing
4%
Size
small
26%
medium
41%
large
33%
Ownership
Government
12%
For profit
53%
Non-profit
34%
Results: Vaccination Rates
Received
Influenza
Vaccine
Received
Pneumococcal
Vaccine
2000-2001
Cohort One
(N=13,267)
2001-2002
Cohort One
(N=13,891)
84.7%
75.9%
53.1%
54.5%