“…The FACIT-fatigue scale has reasonable evidence of validation in a variety of populations, including patients with rheumatoid arthritis [6,7], psoriatic arthritis [8], chronic immune thrombocytopenia [9], Parkinson's disease [10,11], inflammatory bowel disease [12], and systemic lupus erythematosus [13,14], anemic patients with cancer [15,16], as well as the general United States population [17]. It has shown excellent internal consistency and test-retest reliability and also has strong associations with other fatigue measurement tools and with active disease characteristics.…”