Ann. N.Y. Acad. Sci. 966: 320–326 (2002). © 2002 New York Academy of Sciences. Fatigue in Daily Life in Patients with Primary Sjögren’s Syndrome and Systemic Lupus Erythematosus G.L.R. GODAERT, a A. HARTKAMP, b R. GEENEN, a A. GARSSEN, a A.A. KRUIZE, b J.W.J. BIJLSMA, b AND R.H.W.M. DERKSEN b a Department of Health Psychology, Utrecht University, the Netherlands b Department of Rheumatology and Clinical Immunology, UMCU, Utrecht, the Netherlands ABSTRACT: Fatigue is a well-recognized complaint with major impact on daily life in primary Sjögren’s syndrome (PSS) and systemic lupus erythematosus (SLE). Previous research has not taken into account several crucial aspects of fatigue. This study examined various aspects of fatigue in the daily life of patients with PSS and SLE and in healthy controls. We compared age-adjusted, repeated measurements of fatigue across the day of female patients with SLE (n = 20, mean age 43.4 ± 11.3), with PSS ( n = 28, mean age 53.7 ± 13.9) and healthy participants (n = 30, mean age 50.5 ± 13.4). General and physical fatigue was significantly higher in patients than in healthy participants. Groups did not differ with respect to average levels of reduced motivation or mental fatigue. Both general and physical fatigue and reduced activity varied signifi- cantly during the day. Adjusting for depressive symptoms, groups showed sig- nificantly different time courses during the day. In healthy participants and patients with SLE, fatigue first decreased and then increased, whereas a rather opposite course—at least for the first part of the day—was observed in patients with PSS. Using an ecologically valid assessment method, we demonstrated substantially higher levels of daily fatigue in SLE and PSS patients as com- pared to healthy participants, thereby jeopardizing these patients’ quality of life. The effect of disease on variations in fatigue over the day should be the sub- ject of further inquiry, especially as it might clarify underlying mechanisms. KEYWORDS: fatigue; primary Sjögren’s syndrome; systemic lupus erythema- tosus; ambulatory assessment INTRODUCTION Primary Sjögren’s syndrome (PSS) and systemic lupus erythematosus (SLE) are systemic autoimmune disorders in which chronic malaise, especially fatigue, is a well-recognized manifestation with a major impact on daily life. PSS is caused by immune-mediated inflammation and destruction of exocrine glands, and dry mouth and dry eyes are the most prominent complaints. SLE is an immune complex medi- ated multisystem disease that is manifested most frequently by inflammation of Address for correspondence: G.L.R. Godaert, Department of Health Psychology, Utrecht University, the Netherlands. Voice: 31 30 2531785; fax: 31 30 2534718. g.godaert@fss.uu.nl