Quality of Life Projects

Quality of LifeAssessing health-related quality of life in early OA: Development and application of a web-based computerized adaptive measurement system

Tooling up for early osteoarthritis:  Measuring what matters – participation

Grouping Patients with Mild to Severe OA for Research Studies based on Physical Function

Early Osteoarthritis (OA) and its impact on quality of life

Tooling Up for Early Osteoarthritis: evaluating pain and OA management strategies (POAMS)


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.

Introduction and Background
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.


Participant Recruitment

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.

Time Frame and Results

Statistical analyses and dissemination of results (May 2008 - August 2009)

Key Audiences
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 general public.

Relevance 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.

Consumer Involvement

Consumer representatives 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.


Funding Agency

This study is funded by the OA NET grant, which is funded by the CIHR and the Canadian Arthritis Network.


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.


Web links



Project Team Members and Contact Person

Project 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 ckang@arthritisresearch.ca.  

Key Words

Measurement, Computerized Adaptive Testing, Health Utility

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