Presentations and speakers

Prof.dr. Mart van de Laar, MD, PhD

Department of Rheumatology and Clinical Immunology

Medisch Spectrum Twente

Enschede, The Netherlands

Website: http://www.utwente.nl/gw/pgt/mw/laar.doc/

 

 

 

Dr. Peter ten Klooster, PhD

Department of Psychology, Health & Technology

University of Twente

Enschede, The Netherlands

Website: http://www.utwente.nl/gw/pgt/en/emp/klooster/

Emergence of IRT and CAT in health outcomes measurement

Developed in educational and psychological research, IRT and CAT are increasingly gaining ground in health outcomes research. In this presentation, I will give an overview of the possible advantages of these modern measurement methods in clinical research.

Specific applications and developments in the use of IRT and CAT in health measurement will be illustrated by a review of their use in rheumatology.

 

 

Prof.dr. Wim van der Linden, PhD

Chief Research Scientist

CTB/McGraw-Hill

Monterey, CA, USA

Website: http://www.utwente.nl/gw/omd/en/members/vanderlinden/

Adaptive testing: a simple idea finally come true

In spite of its image of statistical sophistication and technological advancement, the use of computerized adaptive testing to measure health outcomes is based on a simple principle that every sensitive oral interviewer applies: if your questions address tasks that are too challenging for the interviewee, you move to simpler tasks; if they are too simple, you make them more challenging. In this presentation, I will discuss the statistical notions and algorithms required to translate this intuitive principle into a modern computerized adaptive testing program.

 

 

Prof.dr. Cees Glas, PhD

Department of Research Methodology, Measurement and Data Analysis

University of Twente

Enschede, The Netherlands

Website: http://www.utwente.nl/gw/omd/en/members/Glas.doc/

Statistical analyses using CAT data

Patient-relevant outcomes, such as impairments, disability and health-related quality of life, are becoming increasingly popular as outcome measures in clinical research. Often, such measures are collected in an IRT-driven CAT. The use of IRT creates both opportunities and problems. The main opportunity is the flexibility it creates in the item-administration design of a trial. The problems are model fit and accounting for the estimation error in the estimates of the latent outcome variables. In this presentation, the following topics will be discussed:

• Parameter estimation in the presence of missing data;

• Estimation of latent regression models and plausible value imputation;

• Model Fit.

An example using data from a longitudinal randomized clinical trial illustrates the use of the methods in a practical setting. It is shown that even when responses on different sets of items for different groups of patients are used for the data analysis, the power to detect the experimental effects is comparable to the power obtained when responses to all items for all patients are used in the analysis.

 

 

Dr. Eswar Krishnan, MD, MPhil

Division of Immunology and Rheumatology

Stanford University School of Medicine

Palo Alto, California, USA

Website: http://med.stanford.edu/profiles/Eswar_Krishnan/

The NIH Patient-Reported Outcomes Measurement System®

To date, the PROMIS project is perhaps the most ambitious effort to bring in item response theory-based approaches to measurement of health status. This talk is meant to inform and update the audience on the history scope and progress made in the PROMIS project in the US. I will also discuss some of the theoretical and practical challenges we have faced in developing and implementing IRT based approaches for self-reported physical function measures.

 

 

 

Prof.dr. Rieki de Vet, PhD

EMGO Institute for Health and Care Research

VU University Medical Center

Amsterdam, The Netherlands

Website: http://www.emgo.nl/team/240/riekiedevet/personal-information/

The PROMIS project in the Netherlands

The Dutch-Flemish PROMIS group has obtained a grant from the Dutch Arthritis Association to translate the NIH-PROMIS item bank. After translation and cross cultural adaptation, the items have to be calibrated and validated.

The presentation will cover some issues of the translation process, but focuses mainly on the validation process, especially on the type of data needed for this project. In the end the benefits of a Dutch PROMIS item bank for research and clinical practice will be discussed.

 

 

Martijn Oude Voshaar, MSc

Department of Psychology, Health & Technology

University of Twente

Enschede, The Netherlands

Website: http://www.utwente.nl/gw/pgt/en/emp/oudevoshaar.doc/

IRT and physical functioning in rheumatology

Physical function is one of the core outcome measures in rheumatology. Traditionally, physical function is assessed by self-report questionnaires in clinical trials and clinical practice. However, the measurement of physical function with fixed length tests is associated with some considerable limitations. The aim of this presentation is to discuss these limitations and to illustrate how computerized adaptive testing can be used to overcome them.

 

 

Stephanie Nikolaus, MSc

Department of Psychology, Health & Technology

University of Twente

Enschede, The Netherlands

Website: http://www.utwente.nl/gw/pgt/en/emp/nikolaus.doc/

Multidimensional measurement of fatigue in patients with rheumatoid arthritis

Fatigue is an important outcome measure in rheumatology. However, there is still no consensus on the best way of measurement. Studies on the patients’ perspective indicate that fatigue is a multidimensional construct. We conducted a Delphi study with rheumatoid arthritis patients and professionals to evaluate fatigue dimensions and items. Based on the results of that study, a multi-dimensional fatigue item pool was developed. At the moment IRT analyses are conducted to be able to select the adequate items for the development of a CAT. Our aim is the construction of a multi-dimensional CAT as an effective fatigue measurement instrument whereby all dimensions of fatigue can be measured without increasing the burden for patients by large numbers of items.

 

 

Liseth Siemons, MSc

Department of Psychology, Health & Technology

University of Twente

Enschede, The Netherlands

Website: http://www.utwente.nl/gw/pgt/en/emp/siemons.doc/

Applying IRT to clinical measures

An increase of IRT applications within rheumatology can be observed. However, applications are mainly targeted at patient-reported outcome measures instead of clinical measures.

In this presentation, I will demonstrate the results of a preliminary study in which both the internal and external construct validity of the 28-tender joint count (TJC-28) were evaluated by applying IRT. The TJC-28 is a clinical measure to assess the status of a rheumatoid arthritis patient, and it forms a major component of disease activity indices.

Based on our preliminary results, some opportunities for a more robust assessment of disease activity in RA patients will be discussed.

 

 

Dr. Peter ten Klooster, PhD

Department of Psychology, Health & Technology

University of Twente

Enschede, The Netherlands

Website: http://www.utwente.nl/gw/pgt/en/emp/klooster/

Using IRT to cross-calibrate outcome measures

Researchers can often choose from a variety of validated tools that measure a specific construct of interest. However, different tools usually consist of different items, rating scales, and scoring procedures, making it difficult to meaningfully interpret results and compare data across studies that have used different tools. One way to overcome this problem is to cross-calibrate scores from different tools that measure the same construct. The aim of this presentation is to demonstrate the use of IRT in cross-calibrating different instruments. This will be illustrated by a study in which two generic measures of physical function, the SF-36 physical functioning scale (PF-10) and the Health Assessment Questionnaire Disability Index (HAQ-DI), were cross-calibrated using data from a large and clinically diverse sample of US adults.

 

 

Dr. Matthias Rose, MD, PhD

Department of Psychosomatic Medicine

University Clinic Eppendorf

Hamburg, Germany

Website: http://www.uke.de/kliniken/psychosomatik/index_49180.php