RESEARCH - The use of self-reporting instruments to assess patients with RA: the longitudinal association between DAS28 and VAS

[Guest guest]

Arthritis Care & Research

Volume 55, Issue 5, Pages 745-750

Published Online: 29 Sep 2006

Comment on the use of self-reporting instruments to assess patients

with rheumatoid arthritis: The longitudinal association between the

DAS28 and the VAS general health

W. Kievit 1 *, P. M. J. Welsing 1, E. M. M. Adang 1, A. M. Eijsbouts

2, P. F. M. Krabbe 1, P. L. C. M. van Riel 1

1Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands

2Sint Maartenskliniek, Nijmegen, The Netherlands

Abstract

Objective

Recently, the use of patient self-reporting instruments instead of

clinical, objective measurements to assess rheumatoid arthritis (RA)

patients was proposed. This assumes a constant association between

disease activity and the self-reporting instruments. The objective was

to explore the association (in time) between disease activity and

patient perception of general health, disease activity, pain, and

functional disability in patients with RA.

Methods

Data of 624 newly diagnosed RA patients who completed 3 years of

followup were analyzed. Cross-sectional linear regression models and

longitudinal regression models were estimated, with a visual analog

scale (VAS) measuring general health (VAS-GH; 0 = best, 100 = worst)

as a dependent variable and the Disease Activity Score (DAS28) without

the VAS-GH as an independent variable. Other dependent variables were

VAS disease activity, pain, and the Health Assessment Questionnaire.

Results

The DAS28 and VAS-GH were significantly associated in RA patients (P <

0.001). However, the explained variance was low (6.7%). From diagnosis

to 3 years after the diagnosis, the intercept decreased given the same

regression coefficient. The longitudinal regression model showed that

the VAS-GH improved during disease course independent of a change in

DAS28. Analyses on the other outcome parameters showed similar

results.

Conclusion

Patients' perception of health can be different with equal disease

activity, depending on the moment in the disease course. Furthermore,

our results indicate that self-reported measures on functionality,

disease activity, and general health cannot substitute for objective

measures of disease activity in RA in longitudinal studies;

subsequently, both need to be measured.

********************************************************************************\

*******

Read the entire article here:

http://www3.interscience.wiley.com/cgi-bin/fulltext/113385279/HTMLSTART

--

Not an MD