145 - Single Item Literacy Screening Questions Are Strongly Associated with Functional Status Among Rheumatoid Arthritis Patients

Sunday, November 6, 2011: 9:00 AM-6:00 PM
Hall F2 - Poster Hall (McCormick Place West)
Liron Caplan, Denver VA and University of Colorado, Aurora, CO, Kaleb D. Michaud, Univ of Nebraska Med Ctr & National Data Bank for Rheumatic Diseases, Omaha, NE, Frederick Wolfe, National Data Bank for Rheumatic Diseases, Wichita, KS and Joel M. Hirsh, Denver Health Med Ctr, Denver, CO
Presentation Number: 145

Background/Purpose: Health Literacy (HL) has been associated with outcomes for a number of conditions and pilot data has linked HL to rheumatoid arthritis (RA) functional status. However, these studies have not adequately accounted for the large number of potential covariates that can influence rheumatoid arthritis outcomes. We examined the association of health literacy with functional status in 5,300 subjects participating in a prospective observational study, controlling for numerous important covariates.

Method:  Using linear regression, we analyzed the cross-sectional association of HL, as measured by two different validated single-item literacy-screening questions (SILS-instruction and SILS-confident), and functional status, assessed by the Health Assessment Questionnaire Disability Index (HAQ). Subjects reported demographics, comorbidities, validated estimates of social support, educational attainment, visual problems, memory problems, as well as prednisone, disease modifying antirheumatic drug, and biologic usage. A stable statistical model was constructed through the use of a backwards stepwise selection procedure with p<0.25 required for variable inclusion. The final model retained only those variables with p<0.05 and each SILS measure, as the variables of interest, were forced into the final model.

Result: Lower HL was present in 6.3% and 3.9% of subjects (per SILS-instruction and SILS-confident). Results (Table 1) were virtually identical for the two SILS instruments, when entered separately into the final model. When controlling for all covariates, lower HL was associated with a 0.369 greater HAQ score, compared to subjects with adequate HL (p<0.001, 95% CI 0.292-0.446). This relationship persisted, even after modeling educational attainment. Visual and memory problems were also associated with more disability, though social support demonstrated no association, after accounting for marital status.

Conclusion: Health literacy was more strongly associated with functional status than prednisone use, smoking history, and biologic use, and this effect was independent of educational attainment. Health literacy may play an important role in understanding functional status in RA patients. Single-item questions amenable to use in the clinical setting may identify subjects with lower HL, who are at risk for poor RA outcomes.

Table 1: Multivariate regression demonstrating variables associated with Health Assessment Questionnaire

Initial Model

Final Model

Variable

Coef.

p

95%

CI

Coef.

p

95%

CI

Age (years)

-0.001

0.577

-0.004

0.002

 

Sex (male)

-0.345

<0.001

-0.407

-0.283

-0.338

<0.001

-0.383

-0.293

Married

0.117

<0.001

0.052

0.182

0.065

0.003

0.022

0.108

SIMSS score

0.036

0.048

0.000

0.072

 

Non-Hispanic White

-0.016

0.779

-0.124

0.093

 

Education (years)

-0.019

0.008

-0.032

-0.005

-0.019

<0.001

-0.028

-0.010

Total Income (per $10K US dollars)

-0.048

<0.001

-0.059

-0.036

0.000

<0.001

0.000

0.000

Vision trouble

0.181

<0.001

0.111

0.251

0.174

<0.001

0.125

0.223

Thinking or memory problems

0.202

<0.001

0.141

0.263

0.185

<0.001

0.144

0.226

Comorbidity Index

0.091

<0.001

0.074

0.108

0.103

<0.001

0.091

0.114

Smoking (years)

0.002

0.060

0.000

0.004

 

Smoking (ever)

0.131

0.825

-1.027

1.289

 

Disease Duration (years)

0.009

<0.001

0.006

0.011

0.009

<0.001

0.007

0.011

Prednisone (current)

0.112

<0.001

0.052

0.171

0.154

<0.001

0.114

0.195

Biologic (ever)

-0.067

0.161

-0.162

0.027

 

Biologic (count)*

0.087

<0.001

0.044

0.130

0.060

<0.001

0.035

0.084

DMARD (ever)

-0.050

0.567

-0.222

0.122

 

Lifetime DMARD & biologic use (count)*

0.024

0.020

0.004

0.044

0.016

0.009

0.004

0.029

Good adherence to RA medications**

0.067

0.107

-0.015

0.149

 

SILS-instruction ***

0.374

<0.001

0.263

0.485

0.369

<0.001

0.292

0.446

SILS-confident ****

0.359

<0.001

0.227

0.491

0.312

<0.001

0.217

0.406

SIMSS=single item measure of social support

DMARD=disease modifying antirheumatic drug

* refers to the number of different medications exposed to from the described class(es)

** Patients who report taking compliance of between 80-120% of their rheumatoid arthritis medication during last month according to the medication adherence self-report inventory (MASRI)  visual analogue scale

*** Patients who responded with "often" or "always" to the question: How often do you need to have someone help you when you read instructions, pamphlets, or other written material from your doctor or pharmacy?

**** Patients who responded with "a little bit" or "not at all" to the question: How confident are you filling out medical forms by yourself?


Keywords: Health Assessment Questionnaire and health education

Disclosure: L. Caplan, UCB, 2 ; K. D. Michaud, None; F. Wolfe, None; J. M. Hirsh, UCB, 2 .