General Health Questionnaire-28: psychometric evaluation of the Slovak version

The EUropean Research on Incapacitating DIseases and Social Support (EURIDISS) is an international longitudinal study focusing on patients with Rheumatoid Arthritis (RA). It elaborates on the impact of the chronic disease on patients’ daily lives. Rheumatoid arthritis, social support and quality of life are the central concepts within the project. Goldberg and Hillier’s 28-item scaled version of the General Health Questionnaire (GHQ-28) has been used to measure the psychological aspect of quality of life. The scale is frequently used in Western Europe, but rarely in Central and Eastern Europe. Slovakia, a Central European country, is joining the EURIDISS project since 1994. Therefore, the question emerged whether the psychometric properties of the Slovak version of the GHQ-28 are adequate in order to measure the psychological component of quality of life. In the present study the reliability and the validity of the GHQ-28 in Slovak RA-patients are evaluated and the outcomes are discussed in the light of Western European (WE) results. The study examines the internal consistency and the factor structure of the instrument. In general, as far as the reliability figures and the intercorrelations of the scales are concerned, the results indicate that the psychometric qualities of the GHQ-28 in Slovakia are satisfactory. However, when taking into consideration the factor structure of the scale, as pointed out by Principal Component Analysis, this reveals several differences. At least six out of the twentyeight items appear to fit better to another subscale than originally was found. Especially, general health ratings, such as ‘felt recently ill’, initially attributed to subscale somatic symptoms, appear to be more closely associated with subscale anxiety/insomnia. More research on GHQ-28 in Central European countries is therefore recommended.