Does Literacy Impact the Effectiveness of
a Disease Management Program in
Congestive Heart Failure?
AcademyHealth 2004 Annual Research Meeting
June 8, 2004
Brad Smith, Robert Ellis, Emma Forkner, Richard A. Krasuski,
Michael Kwan, Karl Stajduhar, Autumn Dawn Galbreath, and
Gregory L. Freeman
Presented by:
Brad Smith
Senior Analyst, Altarum Institute
Project Statistician, UTHSCSA-Disease Management Center
E-mail: brad.smith@altarum.org
Tel: 210-832-3000 Fax: 210-567-9712
www.altarum.org
Introduction

Rising health care expenses have led payors and
health care systems to seek out new approaches to
cost containment for chronic diseases.

Disease management (DM), a comprehensive,
multidisciplinary, therapeutic and educational
intervention, has been shown to improve outcomes
and reduce utilization costs in a number of trials

Published trials have generally been small and have
been conducted in employed, group-insured
populations.
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Introduction

The effectiveness of DM in a more broadly
representative group remains relatively unexplored.

Broader population presents a variety of challenges
to DM including
• Access to primary care and pharmacy
• Literacy
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Introduction

The impact of literacy on the effectiveness of DM is
an important issue to explore given
– The association of literacy with a number of important
chronic disease care outcomes (e.g. AHRQ’s Literacy and Health
Outcomes, 2004 and IOM report on health literacy)
– Centrality of provider-patient communication to the success
of DM programs
– Trends toward expansion of DM programs beyond
employed, group-insured populations (e.g. mandatory DM
for asthma patients in Texas’ Medicaid program)
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Question

How does literacy, as measured by
educational attainment, impact the primary
and secondary outcomes in a randomized,
controlled trial of a disease management
program in congestive heart failure patients?
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Methods: Study Design

Community-based, single-center, randomized,
controlled clinical trial performed between 1999 and
2003 at the University of Texas Health Science
Center at San Antonio

Enrolled a total of 1,069 male and female subjects
18+ years old with documented congestive heart
failure (CHF) from throughout South Texas

Followed patients over 18 months with 4 equally
spaced clinic visits.

This sub-study focuses exclusively on the pooled
DM arms (N=710)
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Methods: DM Intervention

Telephonic intervention by RN with specialized training in CHF
management

Comprehensive written patient education guide in both English
and Spanish targeted to 8th grade reading level

Key components of the disease management intervention
– initiation and upward titration of all recommended drug classes for
CHF
– Verbal instruction and written reference on
• appropriate cardiac diet (low fat, low sodium, fluid restricted)
• medication compliance
• suitable exercise regimen
• appropriate reaction to signs of the onset of a CHF exacerbation.
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Methods: Measures

Primary outcomes
– Clinical: Mortality and event-free survival, ejection fraction, exercise
tolerance
– Utilization: inpatient stays and emergency department visits

Secondary outcomes
– Daily dietary sodium intake in milligrams as measured by the Food
Frequency Questionnaire
– Self-confidence to manage the symptoms of CHF (0-100 ordinal scale)

Independent variables:
– Educational attainment is a proxy for literacy (ordinal)
– Other controls:
• Primary outcome models: type of heart failure, baseline beta blocker status,
NYHA class, gender, race/ethnicity, age
• Secondary outcome models: NYHA class, gender, race/ethnicity, age, primary
language and household composition.
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Sample Profile

Study sample is less
well-educated than
the general
population in South
Texas
– 43.7% HS diploma or
less in study sample
– 34.0% HS diploma or
less in South Texas
(Census statistics)

Sample is otherwise largely Caucasian (70%), male (70%),
older (average age 70.5), English-speaking (94%) and
living with family or spouse (77%)
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Outcomes: Clinical and Utilization Measures

There was no statistically significant difference in
change in ejection fraction, exercise tolerance,
mortality or cardiac event-free survival by
educational attainment.

No statistically significant difference was observed in
the rate of visits to the emergency department or in
the rate of inpatient hospital stays.
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Outcomes: Dietary Sodium Reduction

The likelihood of a reduction in daily sodium intake was
higher among those with at least some college training
than among those with a high school degree or less.

The magnitude of the drop was also larger in the better
educated group.
p=0.012
Some College
0.81
Some College
0.0
HS Diploma or Less
0.73
HS Diploma or less
0.2
0.4
0.6
0.8
-436.4
-600 -500 -400 -300 -200 -100
Predicted Probability of a Drop in Dietary
Sodium Intake
p=0.018
-614.4
0
Decrease in Dietary Sodium Intake
in mg/day
Note: Predicted probabilities computed based on logistic regression results. Size of decrease estimated by OLS.
Both models adjusted for age, sex, race/ethnicity, spanish language and household composition (alone vs not alone)
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Outcomes: Symptom Self-Management Confidence

Confidence in one’s ability to manage the symptoms of CHF
was more likely to increase among those with at least four
years of college than among those with less education.

The magnitude of the difference in the self-confidence scores
between the two groups was not, however, statistically or
substantively significant (2.34 on a 100 pt scale, p=ns).
0.56
Four years or more of college
p=0.025
0.45
Fewer than four years of college
0.0
0.1
0.2
0.3
0.4
0.5
0.6
Predicted Probability of Improvement in Symptom
Self-Management Confidence
Note: Predicted probabilities computed from a logistic regression adjusted for age,
sex, race/ethnicity, Spanish language and household composition (alone vs not alone)
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Conclusions

Educational attainment had a limited impact on the
secondary, but not the primary, outcomes of a disease
management program in CHF.

To gain a more complete picture of how literacy impacts
DM outcomes, it will be critical to develop and employ
state of the art tools for assessment of health literacy in
future studies.
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