Improved Treatment of
Ischemic Heart Disease
and Disability and Death
in the Elderly
Background
„
Changes in health/disability among
population aged 65+ over the past 20 years:
„
„
Kate Stewart
Mary Beth Landrum
David Cutler
Prevalence of chronic diseases increased
Disability decreased
Academy Health
June 27, 2006
Data:
National Long Term Care Survey
Background
„
Does medical care explain some of the
disability decline?
„
„
MedicareMedicare-linked data: hospitalizations & vital
status
Focus: Ischemic Heart Disease
„ Prevalence
increases with age
„ Medical advances reduced mortality by 4040-66%
between 19681968-2000
„ Clinical trials: improved survival and quality of life
„ Little understanding of effect of improved treatment
on population disability
Analytic Cohort:
Baseline Survey
1984
1989
1994
N = 54,453
Data: Medical Treatment
„
Cardiovascular Cooperative Project (CCP),
19941994-1995
„
„
„
„ AceAce-Inhibitors
„
Invasive procedures variable
„
Share of respondents with procedures on the
heart, pericardium or vessels of the heart
N = 3,842
Health Status at
Follow-Up
• Disabled
• Dead
• Alive &
Non-Disabled
Evaluate whether IHD patients living in
HRRs with more intensive treatment had
better outcomes
„
„ Aspirin
Blockers
„ Reperfusion within 12 hours after AMI
1989
1994
1999
Analytic Strategy
Share of appropriate AMI patients within a
hospital referral region (HRR) who received
„ Beta
IHD hospitalization
Minimize selection problems
Natural experiment
„ Exposure
„
„
= treatment intensity
Estimate decline in disability attributable
to improved treatment
Simulate health outcomes by varying levels
of care
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Multinomial Models
Results: Multinomial Models
Model 2: With Tx*
Model 1: Without Tx*
Disabled vs.
NonDisabled
Model 1: Yi,j,t = Xi,tβ + λ1Year89 + λ2Year94
Dead vs.
NonDisabled
Disabled vs.
Non-Disabled
Odds Ratios
Model 2: Yi,j,t = Xi,tβ + λ1Year89 + λ2Year94 +
γCCP Txj + δCCP Txj*Year + τProcsj
^
^λ 1: Year89
^
λ 2: Year94
Dead vs.
Non-Disabled
Odds Ratios
0.83
0.77#
0.90
0.91
0.70#
0.60#
0.83
0.85
-
-
P <0.01
P <0.01
Joint F-test:
treatments
*1984 is reference year
#p
<0.05
Results
Limitations
Simulations by percentiles of care: Number
alive & nonnon-disabled relative to observed
„
AreaArea-level treatment variables
Changes in severity of hospital admissions over
time
„ Differences in claims coding over time
„
300
„
200
No. Elderly (000's)
Potential unmeasured confounding:
100
0
10th
-100
90th
„
-200
-300
CCP treatment variables measured at 1 time
point only
-400
1984
1989
1994
Conclusions
„
„
„
„
Elderly IHD patients were more likely to be
alive & nonnon-disabled over time
Increased treatment explains approx. 50% of
the disability decline
21% more elderly IHD patients would have
been alive and nonnon-disabled in 1999, if all
lived in high treatment areas
Improved care and outcomes possible
through increased use of appropriate IHD
treatments
Funding
„
Funding:
National Institute on Aging (P30 AG12810 and
R01AG019805)
„ Mary Woodard Lasker Charitable Trust
„ Michael E. DeBakey Foundation
„
2
AreaArea-Level Treatment
Results: Health Status at FollowFollow-Up
1984
1989
1994
Difference
1994-1984
% Disabled
23.1
22.3
21.2
-1.9
% Dead
37.7
34.0
31.0
-6.7
% Alive & Nondisabled
39.2
43.7
47.8
8.6
CCP Measures
p-value*
Beta Blockers
AceAce-Inhibitors
Aspirin
0.004
*p-value calculated from pearson chi-square test of independence, corrected for the complex survey design. Estimates
adjusted to the age and sex distribution of the 1999 population of Medicare beneficiaries
Reperfusion
„
Percentiles of Care:
10th
90th
34.7
68.7
46.7
69.7
74.0
84.4
56.2
77.6
Percent Invasive Procedures
„
„
10th percentile: 6% in 1984 and 18% by 1994
90th percentile: 40% in 1984 and 70% by 1994
3