Caroline B. Terwee

Development of a disease specific quality of life questionnaire for patients with Graves’ ophthalmopathy: the GO-QOL

AIM To develop a reliable and valid disease specific quality of life questionnaire (the GO-QOL) for patients with Graves’ ophthalmopathy (GO), that can be used to describe the health related quality of life and changes in health related quality of life over time as a consequence of disease and treatment. METHODS 70 consecutive GO patients (age >18 years) who were referred for the first time to the combined outpatient clinic of the orbital centre and the department of endocrinology completed the 16 questions of the GO-QOL. Additional information on general quality of life and disease characteristics was obtained. Construct validity and internal consistency of the disease specific questionnaire was determined, based on principal component analysis, Cronbach alphas and correlations with MOS-24, three subscales of the SIP, demographic, and clinical measures. RESULTS The a priori expected subdivision of the questionnaire in two subscales, one measuring the consequences of double vision and decreased visual acuity on visual functioning, and one measuring the psychosocial consequences of a changed appearance, was confirmed in the principal component analysis. Both scales had a good reliability and high face validity. Correlations with other measures supported construct validity. Mean scores (range 0–100) were 54.7 (SD 22.8) for visual functioning and 60.1 (24.8) for appearance (higher score = better health). CONCLUSION The GO-QOL is a promising tool to measure disease specific aspects of quality of life in patients with GO and provides additional information to traditional physiological or biological measures of health status.

Test-retest reliability of the GO-QOL: a disease-specific quality of life questionnaire for patients with Graves' ophthalmopathy.

To assess the test-retest reliability of a recently developed disease-specific quality of life questionnaire for evaluative studies in patients with Graves ophthalmopathy (the GO-QOL), measuring visual functioning and psychosocial consequences of changed appearance. Ninety-three patients were included and completed the GO-QOL. Additional information on general quality of life and disease characteristics was obtained. Construct validity and internal consistency of the two subscales was determined, based on principal component analyses, Cronbachs alphas and correlations with MOS-24, three subscales of the SIP, and clinical measures. Eighty-nine patients completed a second GO-QOL after two weeks including four additional questions about perceived changes in health status. Test-retest reliability was assessed by calculating intraclass correlation coefficients (ICCs) and limits of agreement, using several definitions of stable patients. Slight modifications from the original questionnaire were evaluated for their effect on the validity and reliability. The construct validity of the two subscales was confirmed and Cronbachs alphas were 0.89 for visual functioning and 0.87 for appearance. The substantial ICCs found for both scales of the GO-QOL (ICCs above 0.80) reflect that the errors of measurement were relatively small, which supports the value of this questionnaire for clinical studies with relatively small sample sizes. The modification of the appearance scale improved the validity of the scale and resulted in less missing values. Following the recommendations of the joint committee of thyroid associations, we recommend the inclusion of HRQL-measures in clinical studies that evaluate treatments for patients with GO. The GO-QOL is a promising tool for this purpose.

Original articlesTest-Retest Reliability of the GO-QOL: A Disease-Specific Quality of Life Questionnaire for Patients with Graves' Ophthalmopathy

To assess the test-retest reliability of a recently developed disease-specific quality of life questionnaire for evaluative studies in patients with Graves ophthalmopathy (the GO-QOL), measuring visual functioning and psychosocial consequences of changed appearance. Ninety-three patients were included and completed the GO-QOL. Additional information on general quality of life and disease characteristics was obtained. Construct validity and internal consistency of the two subscales was determined, based on principal component analyses, Cronbachs alphas and correlations with MOS-24, three subscales of the SIP, and clinical measures. Eighty-nine patients completed a second GO-QOL after two weeks including four additional questions about perceived changes in health status. Test-retest reliability was assessed by calculating intraclass correlation coefficients (ICCs) and limits of agreement, using several definitions of stable patients. Slight modifications from the original questionnaire were evaluated for their effect on the validity and reliability. The construct validity of the two subscales was confirmed and Cronbachs alphas were 0.89 for visual functioning and 0.87 for appearance. The substantial ICCs found for both scales of the GO-QOL (ICCs above 0.80) reflect that the errors of measurement were relatively small, which supports the value of this questionnaire for clinical studies with relatively small sample sizes. The modification of the appearance scale improved the validity of the scale and resulted in less missing values. Following the recommendations of the joint committee of thyroid associations, we recommend the inclusion of HRQL-measures in clinical studies that evaluate treatments for patients with GO. The GO-QOL is a promising tool for this purpose.

Facial disfigurement: is it in the eye of the beholder? A study in patients with Graves' ophthalmopathy.

objectives The importance of facial disfigurement in many diseases necessitates a reliable and valid measure of disfigurement severity for clinical studies. The hypothesis is that a universal concept of disfigurement exists and can be measured in a reliable way. The objectives of this study were to investigate if persons, in particular patients and physicians, can agree on facial disfigurement severity; and to determine the relative contribution of predefined clinical characteristics of patients with Graves’ ophthalmopathy (GO) to the overall rating of facial disfigurement severity.

Assessment of disease severity

Assessing the severity of Graves’ ophthalmopathy is deceivingly difficult. Some of the initial attempts to assess disease severity were based on the NO SPECS (Table 1; Chapter 1).1 While the idea of a simple numerical index to classify and compare disease severity is appealing, one must recall that this score is a composite of several different observations and measurements. It is exactly for this reason that a composite index should not be used for assessments and reporting results since different parameters can change, in either direction, with no net change in the index score. The optimal method of disease assessment is dependent upon the intent of the measurement. For example, with an individual patient, progression or regression of symptoms and signs of disease is most critical for determining effectiveness. For clinical studies, the amount and location of soft tissue involvement or the “amount” of diplopia may be most relevant for categorizing patients. For patients, being able to function at home or on the job are the most important aspects. The conflict in assessing severity is epitomized by the patients whose CT scans are shown in Figures 1 and 2. One patient has enlargement of all extraocular muscles, but no diplopia while the other patient has intractable diplopia with less enlarged muscles. Furthermore, given that the natural history of the disease consists of a variable period of progressing symptoms and signs over several months followed by a period of stability or improvement, how can the role of immunomodulatory therapy and the optimal time for surgical rehabilitation (e.g. strabismus surgery) be established? (Figs. 1,2; Chapter 4) Depending on the issue, severity of disease can be described utilizing several different techniques.

Quality of Life Measurement in Patients with Graves’ Ophthalmopathy

The measurement of the effects of Graves’ ophthalmopathy (GO) and its treatments on the quality of life of these patients is a new and challenging research area. In this chapter an introduction is given to the methodology of (health-related) quality of life measurement in general and the application of these methods in GO research specifically. Special attention is given to the recently developed GO-specific quality of life questionnaire, the GO-QOL. This questionnaire was specifically developed to be used as an outcome measure for GO research. The development, reliability, validity and interpretation of the GO-QOL are discussed. In the second part of this chapter a state of the art literature review is presented on the use of patient’s perceptions in the description of the impact of GO on the patients’ lives and in the evaluations of treatments for GO.