TennCare Diabetes Program Evaluation
An Individually-Matched Control Group Evaluation of a Disease Management
Program to Improve Quality and Control Costs in a Diabetic Medicaid Population
Presentation to AcademyHealth
Kenton Johnston, MPH, MS, MA
June 4, 2007
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Overview
TennCare Diabetes Program Evaluation
Research Objective:

Evaluate diabetes disease management program for state
Medicaid (TennCare) population

Outcomes of interest: diabetic quality of care and
medical cost savings (Inpatient & Prof/Outpatient)
Outline:

Program Description

Study Design

Findings

Limitations, Conclusions, Implications
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Program Description
TennCare Diabetes Program Evaluation

Outcome of diabetes treatment highly dependent on self-care

Non-adherence to recommended regimens an obstacle to
improved health status

Medicaid population tends to exhibit higher utilization & costs,
as well as poorer health outcomes

CareSmart Diabetes Disease Management (DM) Program –
developed internally by BCBST for TennCare population

For Type 1 and Type 2 diabetics

Program: behavior change & health education, selfmanagement, personalized telephone coaching, compliance
with ADA clinical practice guidelines, and PCP support

Member consent obtained for enrollment in program
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Study Design – Individual Matching With Propensity Model
TennCare Diabetes Program Evaluation

Methodological “toolbox” for DM program evaluation




Randomized controlled trials
Population based pre-post methodology
Predictive modeling
Control group matching (individual, group)

Problem: finding a good control group not easy

Solution: Individually-matched controls using propensity
scores (matched pairs cohort study)



Propensity score is continuous number that represents
individual probability of being in study group
Propensity score reduces entire set of covariates to
one score for easy individual matching
This approach allows for smaller “n”
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Study Design – Population & Methods
TennCare Diabetes Program Evaluation

Study and control group member criteria



Continuously enrolled in TennCare 24-months of 2004-05
Diagnosed with Type 1 or 2 diabetes in 2004 or earlier
Not dually eligible – Medicaid only

126 study members enrolled in CareSmart Diabetes Program
for at least 6 months in 2005 were individually matched to
126 diabetic controls not enrolled in program in 2004 or 2005

Propensity model covariates: demographics, diseases &
comorbidities, quality of care, medical utilization, costs

Baseline Period: Jan - Dec 2004 for matching control & study

Intervention Period: Jan - Dec 2005
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Study Design – Dependent Variables
TennCare Diabetes Program Evaluation

Diabetic quality of care operationally defined according to
recommended preventive services outlined by ADA






Screening for kidney disease
First annual HbA1c screening
Second annual HbA1c screening
Retinopathy screening
LDL cholesterol screening
Medical services utilization and cost





Reported as totals (not specific only to diabetes)
Inpatient admissions, inpatient days, inpatient $$$
ER encounters, office visit encounters, Prof/Outpatient $$$
Total $$$
RX utilization & cost data unavailable
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Findings – Baseline Results
TennCare Diabetes Program Evaluation
Baseline Matching Results - Time Period of Jan - Dec, 2004
N = 126 Matched Pairs
Demographics
Age, MEAN
Gender, % MALE
Morbidity
Orthopedic Conditions & Disorders, %
Coronary Artery Disease, %
Congestive Heart Failure, %
Hypertension, %
Renal Failure, %
Medical Services Utilization
Inpatient Admissions, per person
Inpatient Days, per person
ER Encounters, per person
Office Visit Encounters, per person
Medical Services Allowed Costs
Inpatient, per person
Professional/Outpatient, per person
Total, per person
Diabetic Quality of Care Measures
Screening for Kidney Disease, %
One HbA1c Screening, %
Two HbA1c Screening, %
Retinopathy Screening, %
LDL Screening, %
Overall Diabetic Quality Score, MEAN
Intervention Control
Group
Group
p-value
49.2
21.4%
50.6
25.4%
0.648
0.458
88.9%
24.6%
14.3%
72.2%
3.2%
86.5%
21.4%
17.5%
72.2%
3.2%
0.744
0.550
0.491
1.000
1.000
0.66
2.54
3.26
16.0
0.63
1.99
2.98
15.8
0.563
0.579
0.915
0.447
$ 2,630.17
$ 5,962.77
$ 8,592.94
18.3%
52.4%
32.5%
46.8%
43.7%
1.94
$ 2,405.41 0.358
$ 5,760.52 0.314
$ 8,165.92 0.289
16.7%
50.0%
32.5%
40.5%
43.7%
1.83
0.741
0.706
1.000
0.311
1.000
0.492
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Findings – Intervention Quality Results
TennCare Diabetes Program Evaluation

Statistically significant
positive difference on 4 of 5
measures & on overall score

Improvement in both study &
control groups from 2004

Propensity matched control
group enables us to rule out
secular trend as sole cause
Study Period Results - Time Period of Jan - Dec, 2005
N = 126 Matched Pairs
Diabetic Quality of Care Measures
Screening for Kidney Disease, %
One HbA1c Screening, %
Two HbA1c Screening, %
Retinopathy Screening, %
LDL Screening, %
Overall Diabetic Quality Score, MEAN
Intervention Control
Group
Group
p-value
38.9%
94.4%
71.4%
54.8%
87.3%
3.47
0.004 *
0.008 *
0.013 *
0.001 *
0.169
0.001 *
22.2%
84.1%
56.3%
32.5%
81.0%
2.76
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Findings – Intervention Utilization Results
TennCare Diabetes Program Evaluation


Statistically significant
difference on office visits –
study members had higher
utilization
Office visit finding not
surprising given this is the
setting for quality measures

Inpatient admissions & days
lower for study members –
not statistically significant

ER encounters higher for
study members – not
statistically significant
Study Period Results - Time Period of Jan - Dec, 2005
N = 126 Matched Pairs
Medical Services Utilization
Inpatient Admissions, per person
Inpatient Days, per person
ER Encounters, per person
Office Visit Encounters, per person
Intervention Control
Group
Group
p-value
0.44
1.99
3.09
15.9
0.215
0.179
0.416
0.010 *
0.57
2.97
2.42
12.9
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Findings – Intervention Cost Results
TennCare Diabetes Program Evaluation
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None of the cost findings
were statistically significant
Inpatient & total costs
trending in downward
direction for study group
Prof/Outpatient costs
higher for study group
Financial analysis—using
control group to calculate
expected costs—shows
program savings impact for
study group
Study Period Results - Time Period of Jan - Dec, 2005
N = 126 Matched Pairs
Medical Services Allowed Costs
Inpatient, per person
Professional/Outpatient, per person
Total, per person
Financial Analysis
Base Year 2004 Total $, MEAN per person
Study Year 2005 Total $, MEAN per person
Control Group Total $ Inflation Percentage
Study Group Expected Year 2005 $, per person
Study Group Actual Year 2005 $, per person
Intervention Control
Group
Group
$
$
$
1,894
5,771
7,665
$
$
8,593
7,665
$
$
Study Group Year 2005 Total $ Savings, per person $
$
$
$
p-value
2,806 0.243
5,397 0.099
8,203 0.345
$
8,166 0.289
$
8,203 0.345
0.5%
n/a
8,632 n/a
n/a
7,665 n/a
n/a
967
n/a
n/a
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Limitations
TennCare Diabetes Program Evaluation

Unable to analyze RX data

Psychological or sociological variables not
included/available for propensity model potential source
of confounding

“Non-Participation Bias”


Study members agreed to participate in the program
Controls either could not be contacted by telephone or
refused to participate

We did not control for practice patterns of member
providers (data not available for all members)

Lab values unavailable on > 50% of study and control
population so we were not able to control for these

Available HbA1c and LDL values showed HbA1c close
to stat sig (.09) difference in baseline period
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Conclusions & Implications
TennCare Diabetes Program Evaluation


Conclusions:

Improvement in quality in study group was not due solely to
general secular trend towards quality, but was also positively
impacted by the diabetes program intervention itself

Mixed findings for utilization & cost, but may be showing
trend in right direction
Implications:

DM programs can be successful in improving quality of care
in chronically diseased state Medicaid populations

A matched-pairs cohort study using propensity scores is a
valuable tool for evaluating program outcomes in small to
medium sized populations
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Thank You
TennCare Diabetes Program Evaluation
Presentation to AcademyHealth
Kenton Johnston, MPH, MS, MA
June 4, 2007
E-mail: Kenton_Johnston@BCBST.com
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