Psychometric qualities of the Fatigue Assessment Scale in Croatian sarcoidosis patients.

Background And Aim: Fatigue is an unspecific symptom, but a major problem in sarcoidosis patients. There is a need for a reliable and valid way to measure fatigue. The Fatigue Assessment Scale (FAS) has good psychometric properties in healthy and sarcoidosis samples in the Netherlands, but nothing is known about the psychometric qualities of the FAS in sarcoidosis samples from other countries. Therefore, we examined the reliability, construct, and content validity in Croatian sarcoidosis patients.

Methods: Croatian sarcoidosis patients from a pulmonary outpatient clinic completed the FAS and a symptom inventory questionnaire.

Results: The internal consistency of the FAS was 0.91. Using exploratory factor analysis and Mokken scale analysis, the scale was unidimensional. A dichotomous fatigue item distinguished between individuals who scored high or low on the FAS. Concerning discriminant validity, individuals reporting health complaints were more tired. The FAS correlated moderately with a number of neurological and psychological problems. Females and lower educated individuals reported more fatigue.

Conclusions: The Croatian translation of the FAS has good reliability and validity in a sarcoidosis sample. Future research is needed to explore the psychometric qualities (i) of the Croatian FAS in healthy individuals and (ii) of the FAS in other languages.