health-related quality of life in early OA: Development and
application of a web-based computerized adaptive measurement
up for early osteoarthritis: Measuring what matters
Patients with Mild to Severe OA for Research Studies based
on Physical Function
Osteoarthritis (OA) and its impact on quality of life
Up for Early Osteoarthritis: evaluating pain and OA management
Assessment of Quality of Life in Osteoarthritis: A New Questionnaire
Takes into Account Patients’ Values and Preferences
In the first 4 years
of the NET grant we have developed a new “smart”
quality of life questionnaire (called CAT-5D-QOL) that is
administered on a computer. The computer selects different
questions for different people from a large pool of questions,
depending on their responses. The computer also calculates
the overall health score for each respondent using a complex
mathematical formula. This formula takes into account the
fact that people value different aspects of health differently.
In the present study we will compare the overall scores from
CAT-5D-QOL with other methods of assessing quality of life.
We hope the study will demonstrate the advantages of our new
method and help interpret the scores for researchers and clinicians
using this new instrument as well as decision-makers, patients
and the public in general.
What is the overall impact of disease
on the patient’s quality of life? Several methods can
be used to answer this question. Our method is based on a
complex mathematical formula that combines (self-reported)
information on 5 different aspects of health and function,
such as pain, mobility, performance of daily activities, and
emotional function. The formula uses data from studies designed
specifically to assess how people value different aspects
of health. An important advantage of our method is that the
overall health score is obtained from individual scores on
5 aspects (domains) of health and each domain is measured
with great precision by our new computerized questionnaire.
Other methods of measuring overall health (health-related
quality of life, health utility) either use a single global
question or combine information from a few domains measured
by a single item each. We hope to demonstrate that our instrument
is not only more accurate for the average respondent but also
avoids so called “floor” and “ceiling”
effects – that is, it is able to distinguish between
different levels of health among very healthy and very unhealthy
people. Measuring overall health utility accurately is important
for studies evaluating new treatments, comparing disease burden
across diseases, and performing economic analysis of health
interventions in terms of cost-effectiveness and cost-utility.
Subjects will be
participants in the Physical Activity and Joint Health (PAJH)
study who have explicitly agreed to participate in other studies
(N=1,984). PAJH is an Internet-based cohort study of more
than 4000 members of 50plus.com across Canada. Prospective
participants will receive an email inviting them to complete
an online questionnaire. Three follow-up emails will be sent
at weekly intervals to maximize response rates. As an additional
incentive, participants will have a chance to win cash prizes.
We have previously demonstrated in a randomized trial that
such incentives can increase response rates by 40-50%.
An online questionnaire
will be developed including the CAT-5D-QOL and several other
questionnaires, such as the HUI2/3, EQ-5D, SF-36, and WOMAC.
In addition, we will develop a series of questions to measure
standard gamble and time trade-off utilities using our online
system. We will apply a cross-sectional study design. All
data will be collected via our Internet-based system. Based
on our experience with the PAJH cohort, we expect about 65%
response rate. Data analysis will include descriptive statistics,
comparisons of score distributions, analyses of floor and
ceiling effects, and correlations between different instruments
(the term “correlation” is used to describe the
observed relationship between instances of two events. When
the events involve numbers, a positive correlation means that
as one increases, the other increases as well. A negative
correlation means that as one increases, the other decreases).
We will consider alternative scoring methods for CAT-5D-QOL
that would allow the estimation of different utility scores
from scores based on item response theory models, using advanced
methods of statistical analysis. Ethics approval will be obtained
from the UBC Behavioral Research Ethics Committee.
Frame and Results
analyses and dissemination of results (May 2008 - August 2009)
This is a methodological (instrument development) study and,
therefore, the key audience is other researchers. The results
may also be of interest to clinicians, health policy makers,
patients with chronic conditions such as arthritis, and the
to people living with arthritis
The study is important
for people with arthritis because it will improve the quality
of clinical arthritis research (by improving the accuracy
of measurement) and help better evaluate the burden of arthritis
in the population. This study is a continuation of our long-term
research program aimed at advancing the assessment of quality
of life in people with arthritis and other chronic conditions.
can be involved in designing some components of the online
questionnaire (for example, by pilot testing a preliminary
version of the standard gamble questionnaire) and in KTE activities.
This study is funded
by the OA NET grant, which is funded by the CIHR and the Canadian
Kopec JA, Sayre EC,
Davis AM, Badley EM, Abrahamowicz M, Sherlock L, Williams
JI, Anis A, Esdaile JM. Assessment of health-related quality
of life in arthritis: Conceptualization and development of
five item banks using item response theory. Health Qual Life
Outcomes 2006 Jun 2;4(1):33.
Kopec JA, Badii M, McKenna M, Lima VD, Sayre EC, Dvorak M.
Computerized adaptive testing in back pain: Validation of
CAT-5D. Spine (in press)
Sayre EC, Kopec JA, Abrahamowicz M, Anis AH, Badley EM, Davis
AM, Esdaile JM. Modeling multi-attribute health utility from
five domain-specific IRT scores. International Society for
Quality of Life Research meeting abstracts www.isoqol.org/2007mtgabstracts.pdf].
Quality of Life Research supplement, A-49 Abstract #1598.
Presented at the 14h Annual Meeting of the International Society
for Quality of Life Research, Toronto, October, 2007.
Team Members and Contact Person
team members are Jacek Kopec, Michal Abrahamowicz, Aslam Anis,
Jolanda Cibere, John Esdaile, Carlo Marra, Eric Sayre, Nick
Bansback and Courtney Kang. For more information please contact
Courtney Kang at firstname.lastname@example.org.
Measurement, Computerized Adaptive
Testing, Health Utility