Background: Patients with sarcoidosis frequently complain of fatigue, even when sarcoidosis has come into clinical remission. The primary aim of this study was to assess the severity of fatigue in patients with sarcoidosis in clinical remission and to characterize it according to the international criteria for chronic fatigue syndrome (CFS). Furthermore, we evaluated whether fatigue is associated with depression and anxiety, health status, and patient-reported sleep quality, and we recorded physical activity levels and muscle strength as objective assessments of fatigue.
Methods: Data on 75 patients with sarcoidosis in clinical remission were obtained by questionnaires (Checklist Individual Strength [CIS], Symptom Checklist-90, Beck Depression Inventory for primary care, Medical Outcomes Study 36-Item Short-Form Health Survey), standardized interview (CFS criteria), sleep diary, accelerometer, and muscle strength tests.
Results: Fatigue severity mean score in patients with sarcoidosis in clinical remission was high (CIS fatigue severity 30.5 ± 15.5), and criteria for CFS were met in 47% of fatigued participants. Median time since diagnosis was 9 years. Fatigue was associated with depression (P = .01), anxiety (P = .013), and reduced health status (P < .001). Scores on sleep quality were normal. Physical activity levels were reduced in fatigued participants. Muscle strength, particularly handgrip (P = .006) and quadriceps strength (P < .001), was significantly associated with fatigue.
Conclusions: Fatigue in patients with sarcoidosis in clinical remission is a frequent symptom and can be characterized as a severe and long-lasting problem, symptomatically similar to CFS. Psychologic distress and reduced health status are associated with fatigue. Interestingly, we observed significantly reduced physical activity and muscle weakness in fatigued patients.