Objective: Fatigue is a prominent symptom in primary Sjögren's syndrome (PSS). We set out to compare existing instruments and a new tool for measuring fatigue and general discomfort in PSS, with systemic lupus erythematosus (SLE), rheumatoid arthritis (RA) and healthy controls.
Methods: Groups of female Caucasian PSS patients completed a new questionnaire developed from PSS patients' own vocabulary, as well as the SF-36, WHOQOL-BREF and HAD scales. For comparison, the questionnaire was also completed by groups of SLE and RA patients and healthy controls.
Results: Each disease group differed significantly from healthy controls on each facet of fatigue and general discomfort in the new tool. Somatic fatigue was worst in RA, while mental fatigue was worst in PSS and SLE. The facets of somatic fatigue and discomfort in the new tool correlated well with comparable domains in existing scales.
Conclusions: Fatigue in PSS can be measured using this new Sjögren's-based psychometric instrument. The new questionnaire tool was more sensitive than the SF-36, WHOQOL-BREF and HAD at distinguishing the three rheumatic disorders from controls.