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

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. (Br J Ophthalmol 1998;82:773–779) Graves’ ophthalmopathy (GO), associated with Graves’ thyroid disease (GTD), is an incapacitating eye disease, causing disfiguring proptosis, pain, redness, and swelling of the eyelids, grittiness of the eyes, diplopia, and sometimes even blindness. 2 Several studies have shown that visual problems in general can have a major impact on daily functioning and wellbeing. Furthermore, the psychological burden of the progressive disfigurement resulting from GO is well recognised. 8 Bartley et al 9 report that after treatment 61% of the patients believed that the appearance of their eyes had not returned to baseline status, 51% thought their eyes continued to be abnormal in appearance, and 37% were dissatisfied with the appearance of their eyes. Overall, the eVects of GO on physical and psychological functioning have a significant impact on a patient’s health related quality of life. The outcomes of GO disease and treatment are mostly assessed with biological and physiological measures—for example, combined in the NO SPECS classification. While these measures provide important information to clinicians, they often correlate poorly with functional capacity and perceived health as experienced by the patient. 13 For example, Prummel et al 14 found a response rate of 50% and 46% respectively to prednisone and radiotherapy measured by the NO SPECS classification, but the benefit of both treatments on the subjective judgment of the eye condition by the patient (expressed in the subjective eye score) was only modest. In a recent study we found low correlations between scores on a general health related quality of life questionnaire and measures of severity and activity of disease. These diVerent outcomes can be regarded as diVerent concepts on a causal pathway from biological and physiological measures to perceived symptoms, then to the functional consequences of these symptoms, and finally to more complex elements such as general health perceptions and overall quality of life. Following on the WHO definition of health, health related quality of life (HRQL) can be defined as the physical, psychological, and social domains of health, as perceived by the patient, which are influenced by a patient’s experiences, beliefs, and expectations of their disease and treatment. 17 In general, HRQL measures are among the best predictors of the use of general medical and mental health services as well as strong predictors of mortality. Although implicitly (health related) quality of life always has been an important goal in medicine, it is only quite recently that it became explicitly an outcome measure in medical studies. In 1992, a joint committee of thyroid associations recommended that self assessment of the eye condition by the patient should be included in evaluations of treatments for patients with GO. While a number of studies have assessed Br J Ophthalmol 1998;82:773–779 773 Department of Clinical Epidemiology and Biostatistics, Academic Medical Center, University of Amsterdam, Netherlands