Trends in Care for Uninsured Adults and
Disparities in Care by Insurance Status
Lindsay Sabik
AcademyHealth Annual Research Meeting
June 30, 2009
This material is based upon work supported under a National Science Foundation Graduate Research Fellowship
Outline
•
•
•
•
Background and motivation
D t and
Data
d methods
th d
Results
Summary and discussion
Background and motivation
• Uninsured population increasing over time
• With costs projected to increase, number of uninsured
likelyy to continue rising
g
• Compared to the insured, uninsured individuals
– receive fewer and less timely services
– are less likely to receive preventive care
– have worse outcomes
• Existing research is primarily cross-sectional
Trends in care for uninsured
• Ri
Rising
i costs
t are associated
i t d with
ith
– Advances in medical technology
 Improvements in treatment
 Increasing costs per treatment episode
– Increasing insurance premiums
 Rising number of uninsured
• Tension between improved standards of care and
increasing financial strain on system
Research questions
1)
How is care for the uninsured changing over time?
– Absolute trends indicate whether system maintains
a minimal level of care through safety net
2)
How are the differences in care received by the
privately insured and uninsured changing?
– Relative trends indicate how disparities by
i
insurance
status
t t are changing
h
i over titime
Data
Access:
Communityy Tracking
g
Study
1996-2003
Chronic Care:
National Health and
Nutrition Examination
Survey
1999-2006
Acute Care:
National Hospital
Discharge Survey
1996-2006
1996
2006
Analytic approach
((1)) Restrict sample
p to uninsured individuals and estimate:
Pr (Yit) = Φ (β0 + β1Xi + β2t + εit)
((2)) Include insured and uninsured individuals and estimate:
Pr (Yit ) = Φ (β0 + β1Xi + β2coveragei + β3t
+ β4coveragei·t + εit)
where
Yit = outcome (access/treatment/control) for person i at time t;
Xi = vector
t off individual
i di id l covariates
i t (age, sex, race, income, etc);
coveragei = 1 if privately insured, 0 if uninsured;
t = indicates the time period of the observation;
εit = error term.
Changes in uninsured population
•
Changing population of uninsured affects changes in
care over time
•
Attempt to control for these changes:
– Focus on measures incorporating potential demand
for care
– Focus
F
on sub-populations
b
l ti
off uninsured
i
d with
ith similar
i il
underlying health status
– Include individual-level covariates that control for
observable characteristics associated with health
status and demand for care
CTS sample demographics
Year
Age
% Male
% Nonwhite
Family Income
General Health (1-5)
1996
1998
2000
2003
1996
1998
2000
2003
1996
1998
2000
2003
1996
1998
2000
2003
1996
1998
2000
2003
Privately Insured
(Percent or Mean)
39.9
39.7
40.1***
40.1
40.9***
49.8%
49.5%
49 6%
49.6%
49.1%
21.7%
23.1%***
22 9%
22.9%
23.4%
$49,611
$54,100***
$59 941***
$59,941***
$63,344***
2.14
2.16**
2 20***
2.20***
2.21
Uninsured
(Percent or Mean)
34.8
35.2
35.1
35.9*
53.5%
51.9%
52 7%
52.7%
55.3%**
43.8%
46.1%
46 7%
46.7%
50.7%
$19,571
$19,827
$24 010***
$24,010***
$24,193
2.48
2.50
2 56**
2.56**
2.57
Data from the CTS; Includes individuals ages 18-64; *** p<0.01, ** p<0.05, * p<0.1 in tests of whether value is
significantly different from previous year within insurance category; General health: 1 = Excellent, 5 = Poor.
Forgo care
Access
ccess to
o ca
care
e
• No significant change in
probability of forgoing or
delaying care for uninsured
Forgo or delay care
• Compared to privately
insured, uninsured have
– 9
9.5
5 percentage point higher
probability of forgoing care
– 13.6 percentage point higher
probability of forgoing or
delaying
• No significant changes in
gap
Cholesterol control
Chronic disease
control (1)
• No significant change in
cholesterol or glycemic
gy
control among uninsured
• No significant difference
between privately insured
and uninsured on average
Glycemic control
• U
Uninsured
i
db
become worse
off relative to privately
insured
– increase in gap of ~2pp per
year for cholesterol control
(p<0.05)
– ~1
1 pp per year ffor glycemic
l
i
control (not significant)
Chronic disease control (2)
Blood pressure control
• Both uninsured and
privately insured show
improvements in blood
pressure control
• Gap narrows, though not
significant on average
• ~ 8.1 p
percentage
g p
point
gap remains at end of
period
Invasive care post-AMI
post AMI
Invasive AMI care
• Both uninsured
nins red and
privately insured
improving
• No significant difference
between g
groups
p on
average
• No significant change in
gap between groups
Summary of results
• No significant improvement or decline for uninsured for
most outcome measures
– Flat trends in access; diabetes, cholesterol control
– Exceptions: BP control and post-AMI care
• Gaps between uninsured and privately insured constant
or widening on most measures
Limitations
• Surveyy data limitations
– Access measures from CTS and diagnosis measures
from NHANES based on self-report
– All data are pooled cross-sections
• limits ability to control for changes in population
over time
• Number of possible mechanisms may be driving trends
– e.g. privately
i t l iinsured
d may b
benefit
fit ffrom di
disease
management programs
Implications for policy
• Disparities in access to care and chronic disease control
by insurance are not improving over this period
• Efforts to improve care for the uninsured (e.g. expanding
community health centers) have not narrowed gap for
most measures
• Uninsured are not worse off in an absolute sense, but
are relatively worse off on some measures
– Raises question of whether widening gap is
acceptable