FATIGUE IN PRIMARY SJOGRENS-SYNDROME

Objective-To assess fatigue in relation to depression, blood pressure, and plasma catecholamines in patients with primary Sjogren's syndrome (SS), in comparison with healthy controls and patients with rheumatoi d arthritis. Methods-For the assessment of fatigue the Multidimensiona l Fatigue Inventory (MFI) was used, a 20 item questionnaire, covering the following dimensions: general fatigue, physical fatigue, mental fa tigue, reduced motivation, and reduced activity. Furthermore, the Zung depression scale was used to quantify aspects of depression. Forty ni ne female primary SS patients, 44 female patients with rheumatoid arth ritis (RA), and 32 healthy women filled in both questionnaires. In add ition, supine values of blood pressure and plasma catecholamines were measured in the patients with primary SS. Results-Primary SS patients were more fatigued compared with the healthy controls on all the five dimensions of the MFI. When the analyses were repeated using depressio n as a covariate, group differences disappeared for the dimensions of reduced motivation and mental fatigue. In the primary SS patients, sig nificant positive correlations between depression and the dimensions o f reduced motivation and mental fatigue were found. Comparing patients with primary SS with those with RA, using depression as covariate, no statistically significant differences were found between these groups . No relation between fatigue and blood pressure was found, but a nega tive correlation was observed between the general fatigue subscale of the MFI and plasma noradrenaline. Conclusion-Patients with primary SS report more fatigue than healthy controls on all the dimensions of the MFI and when controlling for depression significant differences remai n on the dimensions of general fatigue, physical fatigue, and reduced activity. The negative correlations between levels of noradrenaline an d general fatigue in patients with primary SS may imply the involvemen t of the autonomic nervous system in chronic fatigue.