Tracking an Epidemic Illness with SelfReport Questionnaires: Ross River Virus Epidemic Polyarthritis

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Tracking an Epidemic Illness with Self-Report
Questionnaires Ross River Virus Epidemic
PolyarthritisFrederick Wolfe1, Kaleb Michaud1,
Tilly Mylonas2, David Purdie2, Nirmala Pandeya2,
Andreas Suhrbier21National Data Bank for
Rheumatic Diseases, Wichita, KS2University of
Queensland, Brisbane, Australia
Abstract
Standardized coefficients and R-squared values
for the study variables
Background. Self-report questionnaires are a part
of every controlled clinical trial and are
increasingly finding their way into clinical
practice. However, there are significant doubts
about the use of what some consider to be
non-objective measures, for self-report
measures represent how the patient feels, and
feelings can be influenced by emotions and
external factors. Therefore, there remain
questions as to how well self-report measures
actual represent disease activity and status. In
1998, Ross River Virus (RRV) illness, an epidemic
polyarthritis, was identified by general
practitioners in Cairns and Brisbane, Australia.
RRV illness is a self-limited illness, but one
associated with severe symptoms. To follow and
document the course of RRV illness, investigators
used self-report questionnaires. We report here
on the ability of these questionnaires to
document the course of RRV polyarthritis. Methods
. At the onset of RRV symptoms, each of 67
patients were assessed with the SF-36 and
CLINHAQ. The CLINHAQ contains the HAQ functional
disability index, as well as scales for pain,
global severity, anxiety and depression. In
addition, self-reported joint involvement was
also recorded. Assessments were repeated at
months 1, 2,3, 6, and 12. Results. The figures
document the course of RRV. The HAQ can be seen
to start at about 0.9, a level similar to that
found in rheumatoid arthritis. The SF-36 PCS
starts at about 30, a distinctly abnormal level.
Elevated levels of anxiety and expression are
also noted. However, by month 3 both the HAQ and
the SF-36 have returned to completely normal
levels. By contrast, anxiety and depression do
not return to 0, but remain slightly elevated
reflecting baseline psychological status.
Conclusions. These data demonstrate that
self-report questionnaires accurately and fully
document physical and emotional status associated
with arthritis and change in arthritis activity.
They also document the extent to which physical
illness causes psychological distress, and how
that distress improves with the resolution of
arthritis. This unique epidemic polyarthritis
provides special insight into the validity and
effectiveness of patient questionnaires.

The standardized coefficients and R-square
values provide information about the relative
strengths of the variables to capture the nature
of the resolving illness. SF-36, patient joint
assessment, and HAQ all perform well, with SF-36
and patient joint assessment performing
performing best.


Summary
Self-report questionnaires document the course of
this self-limited illness very well. Function and
joint involvement scales perform better than
psychological scales SF-36 PCS works slightly
better than the HAQ as it more effectively
captures low levels of functional impairment.
HAQ-II would be expected to be better in this
respect, as well. MCS did not capture the mental
distress in the population. Self-report
questionnaires are effective in documenting
arthritis illness in populations, much as they
are in clinical care.