Fatigue in Patients with Inactive Sarcoidosis Does Not Correlate with Lung Ventilation Ability or Walking Distance. Pilot Study

Introduction: Fatigue is one of many symptoms reported by patients with sarcoidosis. It is believed that fatigue may be the cause of exercise intolerance and reduced quality of life in patients with sarcoidosis. The purpose of the work was to present the frequency of fatigue prevalence in patients with sarcoidosis and to investigate the correlation between fatigue and the results of pulmonary function tests and walking distance. Materials and Methods: A total of 74 patients with sarcoidosis in a stable phase of the disease, not treated in the past with glucocorticoids or immunosuppressive drugs, and without indications for treatment at the time of the study were examined. In all patients fatigue evaluation was carried out with the use of the Fatigue Assessment Scale questionnaire (FAS); dyspnoea was assessed with the use of the Medical Research Council scale (MRC). Body Mass Index (BMI), spirometry, and a 6-minute walk test were additionally performed. The control group included 30 healthy volunteers who completed the FAS. Results: In the examined group of patients fatigue was diagnosed in 36 patients (50%), and in 5 (6.94%)-strong fatigue was observed. The remaining 31 (43.06%) patients felt no fatigue. The average value of points obtained by FAS questionnaire in sarcoidosis patients was significantly higher than the respective value in the control group (p = 0.02). A significantly higher number of points by FAS questionnaire was observed in female patients with sarcoidosis (p = 0.04) in comparison to men. No significant statistical correlation between fatigue index FAS and BMI (r = 0.22, p = 0.11), FEV₁ (r = –0.11, p = 0.3), FEV₁% pred. (r = 0.01, p = 0.9), FVC (r = −0.03, p = 0.77), FEF₂₅₋₇₅ (r = −0.23, p = 0.1) and the distance in the six-minute walk test (6MWT) (r = −0.01, p = 0.9) was observed. However, there was a weak negative correlation between the age of the patients and the FAS index (r = −0.29, p = 0.01). Conclusions: Fatigue in patients with sarcoidosis does not correlate with the results of lung function tests or with walking distance in 6MWT.