BACKGROUND AND AIMS OF THE WORK: Although it often has been suggested that members of patient organisations concerning a particular disease might not be representative of patients with that particular disease in general, this hypothesis has not been tested. Therefore, the aim of this study was to evaluate whether the quality of life (QOL) of members of the Dutch Sarcoidosis Society (DSS) is comparable with the QOL of a random non-member sample of the Dutch sarcoidosis population.
Subjects and methods: The study included 64 out-patients (Group I), 192 DSS members matched for age and gender (Group II), and 192 DSS members matched for age, gender, as well as symptoms (Group III). All subjects filled in a questionnaire to make an inventory of physical symptoms and the World Health Organization Quality of Life assessment instrument (WHOQOL-100). The Student's t-test was used to evaluate the differences between (i) the two DSS groups and (ii) the non-member group.
Results: Group III differed significantly from Group I in only one QOL domain and five facets. Moreover, considering only the patients with symptoms from Group I and Group III, differences emerged on one domain and two facets.
Conclusions: It appeared that more members of the DSS declared they suffered from physical symptoms than non-members. When the experience of symptoms was partialled out fewer QOL differences remained.