Physical Functioning and Symptoms of Chronic Fatigue in Sarcoidosis Patients

Scientific reports underscore the importance of measuring the health-related quality of life in sarcoidosis patients. The present study seeks to define how sarcoidosis patients' quality of life, daily physical activity, and physical performance are related to each other. Seventeen patients (mean age 46.8 ± 8.8 years) suffering from sarcoidosis completed the following questionnaires: the fatigue assessment scale (FAS), the quality of life scale (SF-36 questionnaire), and the Borg dyspnea scale. Physical activity (PA) was assessed using accelerometry. Respiratory function, consisting of forced expiratory volume in one second (FEV1), forced vital capacity (FVC), forced expiratory volume in one second as a percentage of vital capacity (FEV1/%FVC), and diffusing capacity of the lungs for carbon monoxide (DL_CO), were assessed. In addition, performance in 6-min walk test (MWT), aerobic capacity assessed from maximal oxygen uptake (VO₂max), and the metabolic equivalent of task (MET) were evaluated. We found that daily PA (4566 ± 2378 steps/day) and VO₂max (21.8 ± 5.9 ml/kg/min) were lower in sarcoidosis patients than the known predicted values in healthy age-matched individuals. There were significant inverse associations between the FAS score and 6MWT (r = -0.62; p < 0.01), and between SF-36 score and 6MWT (r = -0.55; p < 0.03). In contrast, SF-36 scores associated with fatigue and dyspnea scores (r = 0.72; p < 0.001 and r = 0.85; p < 0.001). These findings imply that sarcoidosis patients are less active compared with healthy subjects. The FAS and SF-36 scales seem to be effective tools for assessing the severity of fatigue in sarcoidosis patients.